Sculpted head of a dignitary from ancient Iran (c.2000 BC) in arsenical copper

 4cm.. Native copper red-orange metallic luster.  Pure copper is orange-red and acquires a reddish tarnish when exposed to air.  " Copper occurs as native copper or in minerals such as the copper sulfides chalcopyrite andchalcocite, the copper carbonates azurite and malachite, and the copper(I) oxide mineral cuprite...

Dilmun: The system of weights used in barter derived from the Indus Valley culture. (Michael Road, Weights on the Dilmun Standard, Iraq, vol. 44, 1982, 137-141). Spreading out from Dilmun, this system of weights became very popular and was used as far away as Ebla in Syria - http://kalyan97.blogspot.com/ [Ebla was gone by 2250 BCE, so this has to be earlier than that.]

Max Mallowan, British archeologist: shell (Cypraea vitellus) from Indian Ocean found in 4000 BC Chagar Bazar, in landlocked northern Syria" (mid-1930s). "A large, organized trading network was flourishing in the area 2000 BCE. One of the most important trading centers was "Ur of the Chaldees.Trade was in the hands of the alik-Dilmun, a group of seafaring merchants, who took the manufactured products of Ur, particularly cloth and readymade clothes, to a city called Dilmun (or Telmun), where they bartered them for copper, red gold, lapis lazuli, ivory and items made from it, eye paint, timber, and "fish-eyes" (pearls?)
"For a long time archeologists have suspected Dilmun to be on the island of Bahrain in the Persian Gulf . . . British archeologist Geoffrey Bibby . . . . discovered the remains of an ancient port on the north coast. Among the many artifacts uncovered there were soapstone stamping seals used to register the contents of a cargo or shipment of goods. . . . an expert on classical archeology in Aarhus, in Denmark, [suggested] that these seals were identical to some found during the excavations in the 1930s at Ur."But even more remarkable was the discovery of similar seals found amid the ruins of the city of Mohejo-Daro in the Indus Valley . . .
"Trade records found at Ur mention two places, Magan and Meluhha . . . It is thought that Magan was on the north shore of the Persian Gulf, in present-day Iran, and that Meluhha, from where Ur received its shells and ivory, is farther away on the coast of the Indian Ocean in the Indus Valley. . . . Five small stone weights, made of polished chert, a flint-like quartz, found in Dilmun were identical in type and weight to those known to have been used in Mohenjo-Daro and its sister-city of Harappa. . . . [Quest for the Past, page 32]

Source: Ancient Pre-history Timeline Concordance 6a (well.com)

Robert James Forbes in Metallurgy in Antiquity: A Notebook for Archaeologists and Technologists suggests the word red (colour) is derived from Sumerian URUD 'copper' which is red. The word 'URUD' of Sumerian is itself likely to be substrate rudhira 'red' (Atharva Veda. v, 29, 10).

 Source: Words for Tin, Copper, Bronze, Gold (well.com)

Indus Script which deploys Meluhha sprachbund 'speech union' of artisans documenting wealth-creation activities, signifies arka 'gold, copper' by a hieroglyph: څرخ ṯs̱arḵẖ > arka 'potter's wheel'; the spokes of the wheel are like arka, 'rays of the sun'; the spokes are cāl 'furrow' rebus: śāla, sal 'workshop'; thus, together, arkasal 'gold-, copper-smith workshop'.

अर्कः, पुं, (अर्च + कर्म्मणि घञ्, कुत्वम् ।) सूर्य्यः ।इन्द्रः । ताम्रं । स्फटिकः । इति मेदिनी ॥ अर्कजौ, पुं, (अर्काज्जायेते यौ, अर्क + जन् ड,पञ्चमीतत्पुरुषः ।) अश्विनीकुमारौ । नित्यद्विव-चनान्तशब्दोऽयं । इति हेमचन्द्रः 

--शब्दकल्पद्रुमः

अर्कज पु० अर्काज्यायते जन--ड ५ त० । १ यमादौ२ तपत्यां ३ यमुनायां च स्त्री ४ अश्विनीकुमारयोःद्वि० ब० । ५ सुग्रीवे ६ कर्ण्णे च । अरुणात्मजशब्दे विवृतिः ।

अर्क पु० अर्च--कर्मणि घञ् कुत्वम् । १ सूर्य्ये, २ इन्द्रे, ३ ताम्रे,४ स्फटिके, ५ विष्णौ, ६ पण्डिते, (आकन्द,) इति ख्याते ७ वृक्षे,(आरख) इति ख्याते ८ क्वाथविशेषे च । ९ अर्चनीये त्रि० ।“आ सूर्य्यो न भानुमद्भिरर्कैः” ऋ० ६, ५, ६ “अर्कैःअर्चनीयैः” भा० “ब्रह्मादिभिः पूज्यमानैरर्चनीयत्वादर्कः”भा० १० ज्येष्ठे” पु० । लक्षणया ११ अर्काधिपे वारे१२ सप्तमीतिथौ १३ उत्तरफल्गुनीनक्षत्रे १४ द्वादशसंख्यायाञ्च तत्र विष्णौ । “अर्को वाजसनः शृङ्गी” वि० सह०अर्कवृक्षे “अर्कः पलाशःखदिरः इति विष्णुध० । सूर्य्ये“अर्काद्विनिःसृतः प्राचीं यद्यात्यहरहः शशी” सूर्य्यसि०“संपर्कादर्करोचिषाम्” माघः “स्प्रष्टुं जगत्पूज्यमयुज्यतार्कः” माघः इन्द्रे अर्कसोदरशब्दे उदा० । अर्कस्यापत्यम्इञ् । आर्किः सूर्यपुत्रे यमादौ, यमुनायां, तपत्याञ्च स्त्रीअरुणात्मजशब्दे विवृतिः ।--वाचस्पत्यम्

Aśvins are venerated in Mahābhārata (1:3-59) in a Sūkta recited by Upamanyu, son of Vyāghrapāda.

अश्विन् aśvin a. अश्व-अस्त्यर्थे इनि] Possessed of horses, consisting of horses; Rv.4.2.5 m. A cavalier, a horse-tamer. -नौ (du.) 1 The two physicians of the gods who are represented as the twin sons of the Sun by a nymph in the form of a mare; cf. त्वाष्ट्री तु सवितुर्भार्या वडवारूपधारिणी । असूयत महाभागा सान्तरीक्षेऽश्विनाबुभौ ॥ [According to Vedic conception they are the harbingers of Uṣas or the dawn; they are young, beautiful, bright, swift &c.; and, according to Yāska, they represent the transition from darkness of light, when the intermingling of both produces that inseparable duality expressed by the twin nature of these deities; according to different interpretations quoted in the Nirukta they were 'heaven and earth', 'day and night', 'two kings, performers of holy acts' which may be traced to their dual and luminous nature. Mythically they were the parents of Nakula and Sahadeva and the physicians of the gods and are called Gadāgadau, Svarvaidyau, Dasrau, Nāsatyau, Vādaveyau, Abdhijau &c. They were celebrated for their active benevolence and curative power which they showed in restoring the sage Chyavana, when grown old and decrepit. to youth, and prolonged his life.] -2 Two horses. -3 (In astr.) The twins of the zodiac. अश्विनी aśvinī [अश्वस्तदुत्तमाङ्गाकारोऽस्त्यस्य इनि ङीप्] 1 The first of the 27 Nakṣatras or lunar mansions (consisting of three stars). -2 A nymph considered in later times as the mother of the Aśvins, the wife of the Sun, who concealed herself in the from of a mare. -Comp. -कुमारौ, -पुत्रौ, -सुतौ the twin sons of Aśvinī, the Sun's wife.(Apte)

Upamanyu is said to be the father or ancestor of sage Kamboja Aupamanyava referred to in the Vamsa Brahmana (1.18) of the Sama Veda.(See Refs: Trans of Rig Veda, III,113, Dr Ludwig; Alt-Indisches Leben, p 102, Dr H. Zimmer; History and Culture of Indian People, The Vedic Age, p 260, Dr R. C. Majumdar, Dr A. D. Pusalkar; Problems of Ancient India, 2000, p 6, K. D. Sethna; Some Kshatriya Tribes of Ancient India, 1924, p 231, Dr B. C. Law; Ancient Kamboja, People and the Country, 1981, Dr J. L. Kamboj; Purana, Vol VI, No 1, Jan 1964, p 212.13 etc.) The patronymic Aupamanyava signifies him as a descendant of Upamanyu, while the name Kamboja suggests an association with the Kamboja kingdom of the (late Vedic) Mahājanapada period. Vamsa Brahamana (1.18-19) of the Sama Veda refers to one Rsi Madragara Shaungayani as the teacher of Aupamanyava Kamboja. As the name itself suggests, risi Madragara Shaungayani belonged to Madra tribe, i.e. the Uttaramadras.

Dr Jain also observes: "Kamboja Aupamanyava, pupil of Madragara, is mentioned in the Vamsa Brahmana. This points to a possible relationship of the Madras or more probably of the Uttaramasdras with the Kambojas, who probably had Indian as well as Iranian affinities".(Ethnology of Ancient Bhārata, 1970, p 108, Dr Ram Chandra Jain.)

Aupamanyava is repeatedly quoted as a grammarian by Yaska in his Nirukta, and also mentioned in respect of the Nisadas and the Panca-janah. ()Political History of Ancient India, 1996, p 134, fn 1, Dr H. C. Raychaudhury, Dr B. N. Mukerjee. NOTE: Dr H. C. Raychaudhury cites reference to Aupamanyava (Nirukta II.2) and identifies him with Kamboja Aupamanyava of the Vamsa Brahmana (Ibid). Aupamanyava is also stated to have authored one Nighantu—a collection of Vedic words. (For references to Aupamanyava Kamboja in Yaska’s Nirukta, see: Dialectics of Hindu Ritualism, 1956, pp 59, Bhupendranātha Datta; Political History of Ancient India, 1996, p 134, Dr H. C. Raychaudhury, Dr B. N. Mukerjee; Also: Kamboja People and the Country, 1981, pp 204-205, Dr J. L. Kamboj; Cultural Sources From the Vedas, 1977, pp 34-35, Sadashiv Ambadas Dange; Cultural Heritage Of India, 1958, pp 292-293, Article contributed by Dr V. D. Aggarwala.) Pt Bhagva Datta points out that, Dr G. Opart has referred to one nirukta (etymology) whose authorship he attributes to a certain Upamanyu.(Catalogue of Sanskrit Manuscripts, Part II, p 510, Dr G Opart.) 

[quote]Commenting on the Vamsa Brahmana list of Vedic teachers, Albrecht Weber writes: "One fact deserves to be especially noticed here, namely, that several of the teachers mentioned in the Vamsa Brahmana, by their very names, points us directly to the north-west of India, e.g. Kamboja Aupamanyava, Madaragara Saungayani, Sati Aushtrakshi, Salamkayana and Kauhala" .(See: The history of Indian literature, 2001 (edition), pp 74/75, fn 71, Albrecht Weber; See also I St., IV, pp 378-80.) And commenting on the same list, R Morton Smith also writes: “The names Kamboja Aupamanyava, Sati Austraksi and Madragara Saungayani suggest a North-west connection for the main branch of Vamsa Brahmana.(Dates and Dynasties: Part III : the Brahmans, 2000, p 79, R Morton Smith - Brahmans.)

Among the entire lists of ancient Vedic teachers of the Satapatha Brahmana as well as the Vamsa Brahmana, Kamboja Aupamanyava appears as the first "Aupamanyava"' (i.e. son or descendant of Upamanyu). This Kamboja Aupamanyava was the guru of Anadaja Chandhanayana who in turn was the guru of Bhanumant Aupamanyava. Bhanumant Aupamanyava (Vamsa Brahmania 16-15) had instructed Urjayant Aupamanyava.(Vamsa Brahmana 15-14)Vedic teachers Bhanumanta Aupamanyava and Urjayant Aupamanyava of the Vamsa Brahmana list were probably the son and grandson of Kamboja Aupamanyava.

Upamanyu also is one of the gotras of Hindu brahmins. The people with Upamanyu gotra live in far western part of Nepal and eastern Parts of Jammu & Kashmir. They are basically present just below the Mount Kailash as they pray to Lord Shiva only. However, according to Dr D. C. Sircar, Upamanyu gotra is not found in early Sanskrit literature and it is difficult to determine at this time whether it is a mistake for Aupamanyava gotra.(Epigraphia Indica, XXXIII, p 193.)

Prof B. N. Datta comments: "...In the list of Brahmana gotras mentioned in the Matsya-Purana, (Matasya Ourana Ch. 195, Sl. 336) the name "Kamboja" is to be found. It is said to be an offshoot of the Vrigu (Bhrigus) gotras. This means that a Rishi hailing from the Kamboja tribe was also founder of a Brahmanical class.......Weber says that the appearance of the name of Kamboja (an Indian-sounding name in Vedic text) as a Sama theologian (Vedic teacher Kamboja Aupamanyava mentioned in Vamsa Brahmana, 18) is analogous of the discovery of the name of Gautama in Zoroastrian Mithra-Yesht.(Indische Studien, herausg, 1858, p 356, Albrecht Friedrich Weber; Monatsberichte der Königlichen preussische Akademie des Wissenschaften zu Berlin, 1858, p 5101, Königlich Preussische Akademie der Wissenschaften zu Berlin.) Upamanyu was of Kamboja descent, and Ushtaxri (Sati Austrakshi) (According to Vamsa Brahmana of Sama-Veda, Sati Aushtrakshi was the teacher of Madaragara Saungayanai. Madragara Saungayani was the guru of Kamboja Aupamanyava who in turn was the guru of Anandaja Chandhanayana. It appears that sage Ushtaxri/Ushtakshri was one of the two gurus of Sati Aushtrakshi, the second being Susravasa Varshaganya (See Vamsa Brahamana verses 18-22)) was probably of Bactrian origin. Further, the name of prominent Rishi like Atharva sounds like Atharavan or Atharvan, the Persian fire-cult priest. The names of Atharva and Angirasa are connected with the introduction of fire-cult amongst the Vedic people. In this case, we find another infiltration of the foreign element (Kambojas etc.) in the ethnic composition of the Vedic Aryas" .(Dialectics of Hindu Ritualism, 1956, p 59, 60, 132, Bhupendranātha Datta.)[unquote]

Source: https://en.wikipedia.org/wiki/Aupamanyava

उपमन्यु upamanyu a. Ved. 1 Understanding, intelligent. -2 Zealous, striving after. -3 (m.) N. of the pupil of Āyoda-dhaumya, who aided Śiva in the propagation of his doctrine and received the ocean of milk from him.(Apte)

Vedic index notes that Ludwig considers Upamanyu to be the name of a person in the Rgveda:

 (Vedic Index)

Vedic index also notes that Aupamanyaviputra is referred to as a teacher in the Baudhayana Srauta Sutra:

(Vedic Index)

Upamanyu was the disciple of sage Ayodhaumya of Avanti...Upamanyu was so hungry that he was forced to it the leaves of Arka (Calotropis gigantea). And his eyes being affected by the pungent, acrimonious, crude, and saline properties of the leaves which he had eaten, he became blind. And as he was crawling about, he fell into a pit. His preceptor soon became concerned with him. While searching for him, he found Upamanyu in the pit. Dhaumya suggested him to summon the physician deities - twin Aswins. So did Upamanyu, Aswins were pleased and offered him a cake to cure him. But Upamanyu would not accept it without offering it to his preceptor. His satisfied the Aswins and they cured him. (Adi Parva, Paushya Parva, page 38-39 

http://www.holybooks.com/mahabharata-all-volumes-in-12-pdf-files/)

Ayodhaumya/ Dhaumya was a sage of Avanti. He had three disciples namely Aruni of Panchal, Upamanyu and Veda. He even accompanied the Pandavas into the forest of Kurujangala during their exile. He sang songs of Sama Veda referring to Yama

.(https://en.wikipedia.org/wiki/List_of_characters_in_the_Mahabharata).

Note: The name ayodhaumya recalls the expression अयस्मय ayasmaya, अयोमय ayomaya a. (-यी f.) Ved. Made of iron or of any metal. -यी N. of one of the three habitations of Asuras. धौम्यः dhaumyaḥ N. of an ancient Ṛiṣi; the family priest of the Pāṇḍavas.

धूमः dhūmaḥ [धू-कम्पे मक्] 1 Smoke, vapour; शिरांस्यपातयत्त्रीणि वेगवद्भिस्त्रिभिः शरैः । सधूमशोणितोद्गारी रामबाणाभिपीडितः ॥ Rām.3.27.18. धूमज्योतिःसलिलमरुतां सन्निपातः क्व मेघः Me.5.-पथः 1 a sacrifice. -2 seeking salvation by religious works; (कर्ममार्ग); जगर्ह सामर्षविपन्नया गिरा शिवद्विषं धूमपथश्रमस्मयम् Bhāg.4.4.10. -3 an air-hole, a window. -पानम् inhaling smoke or vapour. 

Thus ayodhaumya literally signifies working with ayas 'alloy metal' and dhuma 'smoke of bellows'

1.112.08 Showerers (of benefits), with those aids by which you enabled (the lame) Para_vr.j (to walk), the blind (R.jras'va) to see, and (the cripple) S'ron.a to 

go, and by which you set free the quail when seized (by a wolf); with those aids, As'vins, come willingly hither. [Parāvr.j, 

R.rās'va and S'ron.a were r.s.is. Pra_ndha was a totally blind r.s.i (R.jras'va); S'ron.a is said to 

have been made to walk, though not a cripple. Vārttika = quail, may also be a bird like a 

sparrow].

1.116.16 When his father caused,R.jrās'va_, as he was giving to a she-wolf a hundred sheep 

cut up in pieces, to become blind, you, Dasras, physicians (of the gods), gave him eyes (that 

had been) unable to find their way, with which he might see. [R.jrās'va was one of the sons of 

Vr.s.a_gir; a she-wolf: vr.kā was one of the asses of the As'vins in disguise, to test his 

charitable disposition; but, as he exacted the sheep from the people, his father was angry, and 

caused him to lose his eyesight, which the As'vins restored to him].

 (Vedic Index)

(Vedic Index)

अश्विनी, स्त्री, (अश्वः अश्वरूपं विद्यते यस्याः । अश्व+ इन् + ङीप् ।) सप्तविंशतिनक्षत्रान्तर्गतप्रथम-नक्षत्रं । अश्विन्यादयो रेवत्यन्ताः सप्तविंशति-तारा दक्षस्यापत्यत्वात् दाक्षायण्य उच्यन्ते । तत्प-र्य्यायः । अश्वयुक् २ दाक्षायणी ३ । इत्यमरः ॥सा चन्द्रस्य भार्य्या । नवपादात्मकमेषराशेरादि-चतुष्पादरूपा च ॥ अस्या रूपं । घोटकमुखा-कृतितारात्रयात्मकं । अस्या अधिष्ठात्री देवताअश्वारूढपुरुषः । इति ज्योतिःशास्त्रं । तस्यांजातफलं । “सदैव देवाभ्युदितो विनीतः सत्त्वा-न्वितः प्राप्तसमस्तसम्पत् । योषाविभूषात्मज-भूरितोषः स्यादश्विनीजन्मनि मानवस्य” । इतिकोष्ठीप्रदीपः ॥ तस्य मस्तकोपरि उदये कर्कट-लग्नस्य १ । ३० त्रिंशत्पलाधिकदण्डैको गतो भ-वति । यथा । “तन्वि घोटकमुखाकृतौ त्रिभेमस्तकोर्द्ध्वपथभाजि वाजिनि । चारुचन्द्रमुखिकर्कटोदयात् निर्गता गगनरन्ध्रलिप्तिका” ॥ इतिश्रीकालिदासकृतरात्रिलग्ननिर्णयः ॥ --शब्दकल्पद्रुमः

अश्विनीकुमार पु० द्वि० व० । सूर्य्येण त्वष्टृसुतायां संज्ञायांबड़वारूपायामुत्पादितयोः स्वर्वैद्ययोः तदुत्पत्तिकथा भा०आ० प० ६६ अध्याये अश्विनीतनयपुत्रसुतादयोऽप्यत्र ।अरुणात्मजशब्दे २६९ पृ० विवरणम् ।--वाचस्पत्यम्

अश्विनी स्त्री अश्वस्तदुत्तमाङ्गाकारोऽस्त्यस्य इनि ङीप् ।सप्तविंशतिधाविभक्तराशिचक्रस्य प्रथमे भागे । अस्या-स्तथाकारत्वमश्लेषाशब्दे उक्तम् । “अश्निनीमघमूलानांगण्डा आद्यास्त्रिनाड़िकाः” ज्यो० नक्षत्रपरत्वे न० ।“पुष्याश्विहस्ता लघुः” ज्यो० अश्वाया आकारोऽस्त्यस्याः इनिङीप् । हयरूपधारिण्यां त्वष्टृसुतायां ३ सवितुर्भा-र्य्यायामरुणात्मजशब्दे २६९ पृ० विवृतिः ।

अश्विन् पु० द्विव० अश्वाः सन्ति ययोः इनि,अश्विन्यां नक्षत्रे भवौ “सन्धिवेलाद्युतृनक्षत्रेभ्यः पा०अण् “नक्षत्रेभ्योबहुलम्” पा० वा लुक् लुकि स्त्रीप्रत्ययस्यलुक्, अश्वा उत्पत्तिः स्थातत्वेनास्त्यस्य इनि वा ।१ स्वर्गवैद्ययोः । “किमश्विनौ सोमरसं पिपासू” भट्टिः“वासोदश्चन्द्रसालोक्यमश्विसालोक्यमश्वदः” मनुः । “त्वाष्ट्रीतु सवितुर्भार्य्या बडवारूपधारिणी । असूयत महाभागासान्तरीक्षेऽश्विनाबुभौ” भा० आ० प० । “या वां कशामधुमत्यश्विना सुनृतावती” यजु० ७, २ । अश्वस्तच्चिह्नावर्त्तःअस्त्यर्थे इनि । “कपोलयोस्तथावर्त्तौ विद्येते वाजि-नोर्यदि । तावाश्विनाविति प्रोक्तौ राज्यवृद्धिकरौ परौ”इत्युक्तलक्षणयोः २ हययोश्च द्वि० व० । ३ हययुक्ते त्रि० ।स्त्रियां ङीप् । “गोमा अग्नेऽविमाँ अश्वी” ऋ० ४, २, ५ ।

--वाचस्पत्यम्

अश्विनौ, पुं, (प्रशस्ता अश्वाः सन्ति ययोः । इनिः ।यद्वा, अश्विन्याम् जातौ । सन्धिवेलेत्यणो नक्ष-त्रेम्यो बहुलमिति लुकि लुक्तद्वितलुकीति ङीपोलुक् ॥) अश्विनीकुमारौ । इत्यमरः ॥(“त्वाष्ट्री तु सवितुर्भार्य्या वडवारूपधारिणी ।असूयत महाभागा सान्तरीक्षेऽश्विनावुभौ” ॥इति महाभारते ।“किमश्विनौ सोमरसं पिपासू” ।इति भट्टौ ।)(“अश्विनौ देवभिषजौ यज्ञवाहाविति स्मृतौ ।दक्षस्य हि शिरश्छिन्नं पुनस्ताभ्यां समाहितं ॥प्रशीर्णा दशनाःपूष्णो नेत्रे नष्टे भगस्य च ।वज्रिणश्च भुजस्तम्भस्ताभ्यामेव चिकित्सितः ॥चिकित्सितस्तु शीतांशुर्गृहीतो राजयक्ष्मणा ।सोमान्निपतितश्चन्द्रः कृतस्ताभ्यां पुनः सुखी ॥भार्गवश्च्यवनः कामी वृद्धः सन् विकृतिं गतः ।वीतवर्णस्वरोपेतः कृतस्ताभ्यां पुनर्युवा ॥एतैश्चान्यैश्च बहुभिः कम्मभिर्भिषगुत्तमौ ।बभूवतुर्भृशं पूज्याविन्द्रादीनां महात्मनां ॥ग्रहास्तोत्राणि मन्त्राणि तथान्यानि हवींषि च ।धूम्राश्च पशवस्ताभ्यां प्रकल्प्यन्ते द्विजातिभिः ॥प्रातश्च सवने सोमं शक्रोऽश्विभ्यां सहाश्नुते ।सौत्रामण्याञ्च भगवानश्विभ्यां सह मोदते ॥इन्द्राग्नी चाश्विनौ चैव स्तूयन्ते प्रायशो द्विजैः ।स्तूयन्ते वेदवाक्येषु न तथान्या हि देवताः ॥अमरैरजरैस्तावद्विबुधैः साधिपैर्ध्रुवैः ।पूज्येते प्रयतैरेवमश्विनौ भिषजाविति ॥”इति चरकः ॥“श्रूयते हि यथा रुद्रेण यज्ञस्य शिरश्छिन्नमितिततो देवा अश्विनावभिगम्योचुः । भगवन्तौ नःश्रेष्ठतमौ युवां भविष्यथः । भवद्भ्यां यज्ञस्य शिरःसन्धातव्यं । तावूचतुरेवमस्त्विति । अथ तयोरर्थेदेवा इन्द्रं यज्ञभागेन प्रासादयन् । ताभ्यां यज्ञम्यशिरः संहितमिति” ॥ इति सुश्रुतः ॥) --शब्दकल्पद्रुमः

अश्विन् mfn. possessed of horses, consisting of horses, RV.; mounted on horseback, MārkP.;अश्विन् m. a cavalier; अश्विन् n. (= अश्व-वत् n. q.v.) richness in horses, RV. i, 53, 4.; अश्विन् m. du. (इना or इनौ) ‘the two charioteers’, N. of two divinities (who appear in the sky before the dawn in a golden carriage drawn by horses or birds; they bring treasures to men and avert misfortune and sickness; they are considered as the physicians of heaven), RV.  &c. ; a N. of the Nakṣatra presided over by the Aśvins, VarBṛS.; (for अश्वि-सुतौ) the two sons of the Aśvins, viz. Nakula and Sahadeva, MBh. v, 1816; अश्विनी f. N. of the wife of the two Aśvins (who in later times was considered as their mother; cf. अश्विनी-पुत्रौ below), RV. v, 46, 8; the head of Aries or the first of the 28 Nakṣatras, Jyot. ; VarBṛS.   (Monier-Williams)   

1.112.06 With those aids by which you rescued Antaka, (when cast into) a deep (pool), and 

about to be destroyed; by which, inflicting no distress, you preserved Bhujyu, and by which 

you relieved Karkandhu and Vayya; with them, As'vins, come willingly hither. 

[Antaka was a rājaR̥ṣi, whom the asuras threw into a pond or a well; Bhujyu = son of 

Rājā Tugra. Bhujyu had embarked on a maritime expedition against the enemies of his father, but encountered a storm, in which his vessel was lost; he was saved, and brught back to his father by the intervention of the As'vins; Karkabandhu and Vayya: asuras whom the As'vins extricated from misfortunes; cf. RV. I.116.3].

भुज्युः, पुं, (भुज्यतेऽत्रेति । भुज भक्षणे + “भुजिमृङ्भ्यां युक्त्युकौ ।” उणा० ३ । २१ । इतियुक् ।) भाजनम् । इत्युणादिकोषः । २ । २०३ ॥भाजनम् । (भुङ्क्ते सर्व्वानिति । भुज + कर्त्तरियुक् ।) अग्निः । इति संक्षिप्तसारोणादिवृत्तिः ॥(स्वनामख्यातराजविशेषः । यथा, ऋग्-वेदे । ४ । २७ । ४ ।“ऋजिप्य ईमिन्द्रावतो न भुज्युंश्येनो जभार बृहतो अधिष्णोः ॥”भुनक्ति पालयतीति । भुज पालने + युक् ।रक्षके, त्रि । यथा, ऋग्वेदे । ८ । २२ । २ ।“पूर्ब्बापुषं सुहवं पुरुस्पृहं भुज्युं वाजेषु पूर्ब्बम् ॥”“भुज्युं भुजपालने सर्व्वस्य रक्षकम् ॥” इतितद्भाष्ये सायनः ॥)--शब्दकल्पद्रुमः

1.116.03 Tugra, verily, As'vins, sent (his son) Bhujyu to sea, as a dying man parts with his 

riches; but you brought him back in vessels of your own, floating over the ocean, and keeping 

out the waters. [Tugra was a friend of the As'vins; he was annoyed by enemies residing in a 

different island. He sent his son Bhujyu against them, with an army on board a ship; after 

sailing some distance, the vessel foundered in a gale. Bhujyu applied to the As'vins, who 

brought him and his troops back in their own ships, in three days' time].

भुज्यु (for 1. See col.2) wealthy, rich, RV. viii, 22, 1; 46, 20  (Sāy.  = रक्षक; others ‘easily guided’, fr. √1. भुज्); N. of a son of Tugra (protected by the Aśvins),  ib. i, 112, 6; 116, 3  &c.;of a man with the patr. Lāhyāyani, ŚBr. (Monier-Williams) तुग्र m. N. of Bhujyu's father (saved by the Aśvins), RV. i;vi, 62; of an enemy of Indra, 20 and 26; तुग्र्य m. (fr. °र, 115) patr. of Bhujyu, RV. viii ; तुग्र्या f. pl. (scil. विशस्) Tugra's race [‘the waters’ Naigh. i, 12 ] RV. i, 33, 15.   (Monier-Williams)

(Vedic Index)

भुज्युः, पुं, (भुज्यतेऽत्रेति । भुज भक्षणे + “भुजिमृङ्भ्यां युक्त्युकौ ।” उणा० ३ । २१ । इतियुक् ।) भाजनम् । इत्युणादिकोषः । २ । २०३ ॥भाजनम् । (भुङ्क्ते सर्व्वानिति । भुज + कर्त्तरियुक् ।) अग्निः । इति संक्षिप्तसारोणादिवृत्तिः ॥(स्वनामख्यातराजविशेषः । यथा, ऋग्-वेदे । ४ । २७ । ४ ।“ऋजिप्य ईमिन्द्रावतो न भुज्युंश्येनो जभार बृहतो अधिष्णोः ॥”भुनक्ति पालयतीति । भुज पालने + युक् ।रक्षके, त्रि । यथा, ऋग्वेदे । ८ । २२ । २ ।“पूर्ब्बापुषं सुहवं पुरुस्पृहं भुज्युं वाजेषु पूर्ब्बम् ॥”“भुज्युं भुजपालने सर्व्वस्य रक्षकम् ॥” इतितद्भाष्ये सायनः ॥) --शब्दकल्पद्रुमः

4.027.04 The straight-flying hawk carried off the Soma from above the vast heaven, as (the As'vins carried off) Bhujyu from the region of Indra, and a falling feather from the middle of the bird dropped from him wounded in the conflict. [antah parn.am tan madhye sthitam; one nail of the left foot and the shaft was broken by the collision, the fragments of the nail became the quills of the fretful porcupine, those of the arrow, water-snakes, flying foxes, and worms].

8.046.20 O bountiful, mos bountiful, mighty, wonderful, best giver of knowledge and supremely truthful, by your prowess, universal ruler, (bring to us) in conflicts ample wealth, overpowering those who attack us, and causing enjoyment. [bhujyam, pu_rvyam: two epithes applied in RV 8.22.2 to the chariot of the As'vins; pu_rvya = going before (in battle); bhujyu = preserver of all].

1.116.11 Nāsatyas, leaders, glorious was that exploit of yours, one to be celebrated, to be 

adored, to be desired by us, when, becoming aware (of the circumstance), you extricated 

Vandana_, (hidden), like a concealed treasure, from the (well) that was visible (to travellers). 

[dars'atāt, well, i.e. that which was to be seen by thirsty travellers].

नासत्य b mfn. (prob. fr. √2. नस्, Caus.) helpful, kind, friendly (mostly m. du. as N. of the Aśvins, RV. ; later m. sg. N. of one of the A°s, the other being then called Dasra); relating or belonging to the A°s MBh.नासत्या f. the constellation Aśvinī, L.  (The derivations fr. न + असत्य, 

or fr. नासा + त्य or fr. ना + सत्य are very improbable.) (Monier-Williams)

See: jayasreesaranathan.blogspot.com/2018/12/unknown-rig-vedic-hymn-on-asvins-in.html In this blogpost, the expression r̥gbhih in MBh text is interpreted as a r̥ca composed to invoke the two Aśvins for a cure from blindness. 

I submit that in the expression used in MBh r̥ca means 'song of praise'; cognate: अर्क arka 'praise, hymn; praising, extolling, song of praise' (Apte).

The translation by Kisari Mohan Ganguli interprets the expression,  r̥gbhih, occurring in the text as a R̥gveda Sukta.

I do not speculate on the reasons why the Sukta rendered by Upamanyu in the Great Epic does not occur in the R̥gveda samhita. 

परीक्षॊपमन्यॊः ‘Trial of Upamanyu’

Trial of Upamanyu is narrated in the Great Epic. Here’s the text and translation into English by Kisari Mohan Ganguly:

महाभारतम्-01-आदिपर्व-003 

[quote]

51 स कदा चिद अरण्ये कषुधार्तॊ ऽरकपत्राण्य अभक्षयत

52 स तैर अर्कपत्रैर भक्षितैः कषार कटूष्ण विपाकिभिश चक्षुष्य उपहतॊ ऽनधॊ ऽभवतसॊ ऽनधॊ ऽपि चङ्क्रम्यमाणः कूपे ऽपतत

53 अथ तस्मिन्न अनागच्छत्य उपाध्यायः शिष्यान अवॊचत मयॊपमन्युः सर्वतः परतिषिद्धः स नियतं कुपितः ततॊ नागच्छति चिरगतश चेति

54 स एवम उक्त्वा गत्वारण्यम उपमन्यॊर आह्वानं चक्रे भॊ उपमन्यॊ कवासि वत्सैहीति

55 स तदाह्वानम उपाध्यायाच छरुत्वा परत्युवाचॊच्चैः अयम अस्मि भॊ उपाध्याय कूपे पतित इति

56 तम उपाध्यायः परत्युवाच कथम असि कूपे पतित इति

57 स तं परत्युवाच अर्कपत्राणि भक्षयित्वान्धी भूतॊ ऽसमि अतः कूपे पतित इति

58 तम उपाध्यायः परत्युवाच अश्विनौ सतुहि तौ तवां चक्षुष्मन्तं करिष्यतॊ देव भिषजाव इति

59 स एवम उक्त उपाध्यायेन सतॊतुं परचक्रमे देवाव अश्विनौ वाग्भिर ऋग्भिः

60 परपूर्वगौ पूर्वजौ चित्रभानू; गिरा वा शंसामि तपनाव अनन्तौ दिव्यौ सुपर्णौ विरजौ विमानाव; अधिक्षियन्तौ भुवनानि विश्वा

61 हिरण्मयौ शकुनी साम्परायौ; नासत्य दस्रौ सुनसौ वैजयन्तौ शुक्रं वयन्तौ तरसा सुवेमाव; अभि वययन्ताव असितं विवस्वत

62 गरस्तां सुपर्णस्य बलेन वर्तिकाम; अमुञ्चताम अश्विनौ सौभगाय तावत सुवृत्ताव अनमन्त मायया; सत्तमा गा अरुणा उदावहन

63 षष्टिश च गावस तरिशताश च धेनव; एकं वत्सं सुवते तं दुहन्ति नाना गॊष्ठा विहिता एकदॊहनास; ताव अश्विनौ दुहतॊ घर्मम उक्थ्यम

64 एकां नाभिं सप्तशता अराः शरिताः; परधिष्व अन्या विंशतिर अर्पिता अराः अनेमि चक्रं परिवर्तते ऽजरं; मायाश्विनौ समनक्ति चर्षणी

65 एकं चक्रं वर्तते दवादशारं; परधि षण णाभिम एकाक्षम अमृतस्य धारणम यस्मिन देवा अधि विश्वे विषक्तास; ताव अश्विनौ मुञ्चतॊ मा विषीदतम

66 अश्विनाव इन्द्रम अमृतं वृत्तभूयौ; तिरॊधत्ताम अश्विनौ दासपत्न भित्त्वा गिरिम अश्विनौ गाम उदाचरन्तौ; तद वृष्टम अह्ना परथिता वलस्य

67 युवां दिशॊ जनयथॊ दशाग्रे; समानं मूर्ध्नि रथया वियन्ति तासां यातम ऋषयॊ ऽनुप्रयान्ति; देवा मनुष्याः कषितिम आचरन्ति

68 युवां वर्णान विकुरुथॊ विश्वरूपांस; ते ऽधिक्षियन्ति भुवनानि विश्वा ते भानवॊ ऽपय अनुसृताश चरन्ति; देवा मनुष्याः कषितिम आचरन्ति

69 तौ नासत्याव अश्विनाव आमहे वां; सरजं च यां बिभृथः पुष्करस्य तौ नासत्याव अमृतावृतावृधाव; ऋते देवास तत परपदेन सूते

70 मुखेन गर्भं लभतां युवानौ; गतासुर एतत परपदेन सूते सद्यॊ जातॊ मातरम अत्ति गर्भस ताव; अश्विनौ मुञ्चथॊ जीवसे गाः

71 एवं तेनाभिष्टुताव अश्विनाव आजग्मतुः आहतुश चैनम परीतौ सवः एष ते ऽपूपः अशानैनम इति

72 स एवम उतः परत्युवाच नानृतम ऊचतुर भवन्तौ न तव अहम एतम अपूपम उपयॊक्तुम उत्सहे अनिवेद्य गुरव इति

73 ततस तम अश्विनाव ऊचतुः आवाभ्यां पुरस्ताद भवत उपाध्यायेनैवम एवाभिष्टुताभ्याम अपूपः परीताभ्यां दत्तः उपयुक्तश च स तेनानिवेद्य गुरवे तवम अपि तथैव कुरुष्व यथा कृतम उपाध्यायेनेति

74 स एवम उक्तः पुनर एव परत्युवाचैतौ परत्यनुनये भवन्ताव अश्विनौ नॊत्सहे ऽहम अनिवेद्यॊपाध्यायायॊपयॊक्तुम इति

75 तम अश्विनाव आहतुः परीतौ सवस तवानया गुरुवृत्त्या उपाध्यायस्य ते कार्ष्णायसा दन्ताः भवतॊ हिरण्मया भविष्यन्ति चक्षुष्मांश च भविष्यसि शरेयश चावाप्स्यसीति

76 स एवम उक्तॊ ऽशविभ्यां लब्धचक्षुर उपाध्याय सकाशम आगम्यॊपाध्यायम अभिवाद्याचचक्षे स चास्य परीतिमान अभूत

77 आह चैनम यथाश्विनाव आहतुस तथा तवं शरेयॊ ऽवाप्स्यसीति सर्वे च ते वेदाः परतिभास्यन्तीति

78 एषा तस्यापि परीक्षॊपमन्यॊः

 "And Upamanyu, one day, oppressed by hunger, when in a forest, ate of the leaves of the Arka (Asclepias gigantea). And his eyes being affected by the pungent, acrimonious, crude, and saline properties of the leaves which he had eaten, he became blind. And as he was crawling about, he fell into a pit. And upon his not returning that day when the sun was sinking down behind the summit of the western mountains, the preceptor observed to his disciples that Upamanyu was not yet come. And they told him that he had gone out with the cattle. "The preceptor then said, 'Upamanyu being restrained by me from the use of everything, is, of course, and therefore, doth not come home until it be late. Let us then go in search of him.' And having said this, he went with his disciples into the forest and began to shout, saying, 'Ho Upamanyu, where art thou?' And Upamanyu hearing his preceptor's voice answered in a loud tone, 'Here I am at the bottom of a well.' And his preceptor asked him how he happened to be there. And Upamanyu replied, 'Having eaten of the leaves of the Arka plant I became blind, and so have I fallen into this well.' And his preceptor thereupon told him, 'Glorify the twin Aswins, the joint physicians of the gods, and they will restore thee thy sight.' And Upamanyu thus directed by his preceptor began to glorify the twin Aswins, in the following words of the Rig Veda:

'Ye have existed before the creation! Ye first-born beings, ye are displayed in this wondrous universe of five elements! I desire to obtain you by the help of the knowledge derived from hearing, and of meditation, for ye are Infinite! Ye are the course itself of Nature and intelligent Soul that pervades that course! Ye are birds of beauteous feathers perched on the body that is like to a tree! Ye are without the three common attributes of every soul! Ye are incomparable! Ye, through your spirit in every created thing, pervade the Universe! "Ye are golden Eagles! Ye are the essence into which all things disappear! Ye are free from error and know no deterioration! Ye are of beauteous beaks that would not unjustly strike and are victorious in every encounter! Ye certainly prevail over time! Having created the sun, ye weave the wondrous cloth of the year by means of the white thread of the day and the black thread of the night! And with the cloth so woven, ye have established two courses of action appertaining respectively to the Devas and the Pitris. The bird of Life seized by Time which represents the strength of the Infinite soul, ye set free for delivering her unto great happiness! They that are in deep ignorance, as long as they are under delusions of their senses, suppose you, who are independent of the attributes of matter, to be gifted with form! Three hundred and sixty cows represented by three hundred and sixty days produce one calf between them which is the year. That calf is the creator and destroyer of all. Seekers of truth following different routes, draw the milk of true knowledge with its help. Ye Aswins, ye are the creators of that calf! "The year is but the nave of a wheel to which is attached seven hundred and twenty spokes representing as many days and nights. The circumference of this wheel represented by twelve months is without end. This wheel is full of delusions and knows no deterioration. It affects all creatures whether to this or of the other worlds. Ye Aswins, this wheel of time is set in motion by you! "The wheel of Time as represented by the year has a nave represented by the six seasons. The number of spokes attached to that nave is twelve as represented by the twelve signs of the Zodiac. This wheel of Time manifests the fruits of the acts of all things. The presiding deities of Time abide in that wheel. Subject as I am to its distressful influence, ye Aswins, liberate me from that wheel of Time. Ye Aswins, ye are this universe of five elements! Ye are the objects that are enjoyed in this and in the other world! Make me independent of the five elements! And though ye are the Supreme Brahma, yet ye move over the Earth in forms enjoying the delights that the senses afford. "In the beginning, ye created the ten points of the universe! Then have ye placed the Sun and the Sky above! The Rishis, according to the course of the same Sun, perform their sacrifices, and the gods and men, according to what hath been appointed for them, perform their sacrifices also enjoying the fruits of those acts!

"Mixing the three colours, ye have produced all the objects of sight! It is from these objects that the Universe hath sprung whereon the gods and men are engaged in their respective occupations, and, indeed, all creatures endued with life! "Ye Aswins, I adore you! I also adore the Sky which is your handiwork! Ye are the ordainers of the fruits of all acts from which even the gods are not free! Ye are yourselves free from the fruits of your acts! "Ye are the parents of all! As males and females it is ye that swallow the food which subsequently develops into the life creating fluid and blood! The new-born infant sucks the teat of its mother. Indeed it is ye that take the shape of the infant! Ye Aswins, grant me my sight to protect my life!" The twin Aswins, thus invoked, appeared and said, 'We are satisfied. 

Here is a cake for thee. Take and eat it.' 

And Upamanyu thus addressed, replied, 'Your words, O Aswins, have never proved untrue. But without first offering this cake to my preceptor I dare not take it.' And the Aswins thereupon told him, 'Formerly, thy preceptor had invoked us. We thereupon gave him a cake like this; and he took it without offering it to his master. Do thou do that which thy preceptor did.' Thus addressed, Upamanyu again said unto them, 'O Aswins, I crave your pardon. Without offering it to my preceptor I dare not apply this cake.' 

The Aswins then said, 'O, we are pleased with this devotion of thine to thy preceptor. Thy master's teeth are of black iron. Thine shall be of gold. Thou shall be restored to sight and shall have good fortune.'"Thus spoken to by the Aswins he recovered his sight, and having gone to his preceptor's presence he saluted him and told him all. And his preceptor was well-pleased with him and said unto him, 'Thou shalt obtain prosperity even as the Aswins have said. All the Vedas shall shine in thee and all the Dharma-sastras.' And this was the trial of Upamanyu. [unquote]

https://ia800302.us.archive.org/34/items/TheMahabharataOfKrishna-dwaipaya1naVyasa/MahabharataOfVyasa-EnglishTranslationByKMGanguli.pdf

[quote]Cuprum (Copper) - Elementymology & Elements Multidict (vanderkrogt.net)