As a hieroglyph/hypertext, akṣa signifies a wheel.अक्ष m. an axle , axis (in this sense also n.; a wheel , car, cart (Monier-Williams) Rebus: akṣa signifies a weight called कर्ष , equal to 16 माषs and also refers to an ancient coin called akkam, 1/12 of  कर्ष (which is the root word for English 'cash').The pinnacle of achievement in Bronze Age Revolution relates to the invention of cire perdue technique of metal castings to produce metal alloy sculptures of breath-taking beauty. The quantum leap in knowledge systems occurred when the artifact was designed to signify in an Indus Script hypertext writing system, a goldsmith's workshop. 

Sign 391

The spoked wheel made of copper alloy signifies akṣaracaṇa 'scribe'; and agasāle 'goldsmith, i.e. one who has a shop working with gold'.(Kannada) 

 

śāˊlā f. ʻ shed, stable, house ʼ AV., śālám adv. ʻ at home ʼ ŚBr., śālikā -- f. ʻ house, shop ʼ lex.Pa. Pk. sālā -- f. ʻ shed, stable, large open -- sided hall, house ʼ, Pk. sāla -- n. ʻ house ʼ; Ash. sal ʻ cattleshed ʼ, Wg. šāl, Kt. šål, Dm. šâl; Paš.weg. sāl, ar. šol ʻ cattleshed on summer pasture ʼ; Kho. šal ʻ cattleshed ʼ, šeli ʻ goatpen ʼ; K. hal f. ʻ hall, house ʼ; L. sālh f. ʻ house with thatched roof ʼ; A. xāl, xāli ʻ house, workshop, factory ʼ; B. sāl ʻ shed, workshop ʼ; Or. sāḷa ʻ shed, stable ʼ; Bi. sār f. ʻ cowshed ʼ; H. sāl f. ʻ hall, house, school ʼ, sār f. ʻ cowshed ʼ; M. sāḷ f. ʻ workshop, school ʼ; Si. sal -- a, ha° ʻ hall, market -- hall ʼ.(CDIAL 12414) शाला f. (ifc. also n(शाल).) a house , mansion , building , hall , large room , apartment , shed , workshop , stable AV. &c ([cf. Germ. saal ; Eng.hall])

The cire perdue spoked wheel of copper+lead alloy was NOT an amulet, it was a metal artifact, a metal coin, akkam; it was a compartmental Harappa seal with Harappa (Indus) Script hieroglyph. May or may not have been used as a coin to value and exchange goods but a proclamation of the metallurgical excellence achieved by Bharatam Janam of 4th millennium BCE and the invention of writing by akṣaracaṇa 'scribe' (Kannada) signified by the Mehrgarh spoked wheel amulet. I also suggest that the invention of the Indus Script Hypertext of a spoked wheel to signify a 'scribe' is an invention by a goldsmith, akkasāliga.(an expression derived from the root akṣa अक्ष m. an axle , axis (in this sense also n.); a wheel , car , cart [cf. Lat. axis ; Old Germ.ahsa ; Mod. Germ. Achse; Lith. assis.]; a weight called कर्ष , equal to 16 माषs (Monier-Williams) akṣḥ अक्षः [अश्-सः] 1 An axis, axle, pivot; अक्षभङ्गे च यानस्य....न दण्डं मनुरब्रवीत् Ms.8.291,292; दृढधूः अक्षः Kāś. V. 4.74; Śi.12.2, 18.7; ज्योतिश्चक्राक्षदण्डः Dk. 1 Axle-pole. -2 The pole of a cart. -3 A cart, car; also a wheel; -चक्रम् the circle of sensual passions. दृढनियमित ˚क्रः K.37 (also axis and wheels);  -वाटः [अक्षाणां पाशकक्रीडानां बाटः वासस्थानम्] 1 a gambling house; the gambling table. -2 [अक्षस्य रथचक्रस्य क्षुण्णस्थानस्य इव वाटः] a place of contest, arena, wrestling ground (तत्र हि रथचक्रक्षुण्णपांशुसदृशपांशुम- त्त्वात् तत्सदृशत्वम् Tv.) -विदa. skilled in gambling. -वृत्त a. [अक्षे वृत्तः व्यापृतः स. त.] engaged in, addicted to, gambling; what has occurred in gambling (Apte) अक्ष m. an axle , axis (in this sense also n.; a wheel , car , cart (Monier-Williams).

अर्क m. ( √ अर्च्) , Ved. a ray , flash of lightning RV. fire RV. ix , 50 , 4; fire (शतपथ-ब्राह्मण; बृहद्-ारण्यक-उपनिषद्); the sun (RV). Rebus: अर्क a learned man (cf. RV. viii , 63 , 6) Rebus: अर्क copper; அருக்கம்¹arukkam, n. < arka. (நாநார்த்த.) 1. Copper; செம்பு. 2.Crystal; பளிங்கு. அக்கம்&sup4; akkam , n. < arka. An ancient coin = 1/12 காசு; ஒரு பழைய நாணயம். (S. I. I. ii. 123.)

akka-cālai *அக்கசாலை akka-cālai, n. < arka +. 1. Metal works; பொன் முதலிய உலோக வேலை செய்யு மிடம். (சிலப். 16, 126, உரை.) 2. Mint; நாணயசாலை. (W.) 

ákṣa1 m. ʻ axle ʼ RV., ʻ collar -- bone ʼ ŚBr., ʻ temporal bone ʼ Yājñ., akṣaka -- m.n. ʻ collar -- bone ʼ Suśr. [Perh. conn. ákṣu -- ]Pa. akkha -- m. ʻ axle ʼ, °aka -- m. ʻ collar-bone ʼ; Pk. akkha<-> m. ʻ collar-bone ʼ, KharI. akha -- ; Or. akha ʻ axle-tree ʼ; Bi. akhaut ʻ axle of grain -- husker ʼ, akhautā ʻ do. of brick -- crusher ʼ (+ ?); G. ã̄k m. ʻ axle ʼ, M. ās, ã̄s m. ʻ axle, temple of head ʼ (→ G. ã̄s m. ʻ axis ʼ), ã̄kh m. ʻ axle ʼ; Si. aka ʻ axle ʼ, akuva ʻ collar -- bone ʼ (< akṣaka -- Geiger GS 30).(CDIAL 21)*akṣakīla cf. akṣāgrakīla -- , °aka -- m. ʻ lynch -- pin ʼ lex. [ákṣa -- 1, kīla -- ]Bi. (Patna) akhailā ʻ axle of brick -- crusher ʼ.(CDIAL 26)akṣadhur f. ʻ pin or pole of axle ʼ. [ákṣa -- 1, dhúr -- ]M. ākhrī, akh° f. ʻ beam over the axle on which the frame of the cart rests ʼ; Si. akura ʻ axle of a wheel ʼ.(CDIAL 31)*akṣākāra ʻ shaped like a die ʼ. [akṣá -- 2, ākāra -- ]H. akhār m. ʻ a small lump of clay placed in the centre of a potter's wheel ʼ.(CDIAL 40)  आस or आंस āsa or āṃsa m (अक्ष S) An axle. (Marathi)

[quote]Bourgarit and Mille (Bourgarit D., Mille B. 2007. Les premiers objets métalliques ont-ils été fabriqués par des métallurgistes ? L’actualité Chimique . Octobre-Novembre 2007 - n° 312-313:54-60) have  reported the finding (probably in the later still unreported excavation period) of small Chalcolithic “amulets” which they claim to have been produced by the process of Lost Wax. According to them, “The levels of the fifth millennium Chalcolithic at Mehrgarh have delivered a few amulets in shape of a minute wheel, while the technological study showed that they were made by a process of lost wax casting. The ring and the spokes were modelled in wax which was then coated by a refractory mould that was heated to remove the wax. Finally, the molten metal was cast in place of the wax. Metallographic examination confirmed that it was indeed an object obtained by casting (dendrite microstructure). This discovery is quite unique because it is the earliest attestation of this technique in the world.” They then, further on, state that “The development of this new technique of lost wax led to another invention, the development of alloys...Davey (Davey C. 2009.The Early History of Lost-Wax Casting, in J. Mei and Th. Rehren (eds), Metallurgy and Civilisation: Eurasia and Beyond Archetype, pp. 147-154. London: Archetype Publications Ltd.) relies only upon these Mehrgarh findings , as well as on the Nahal Mishmar hoard, to claim that Lost Wax casting began in the Chalcolithic period before 4000 BCE.” [unquote]  (Shlomo Guil) 

https://www.academia.edu/5689136/Reflections_Upon_Accepted_Dating_of_the_Prestige_Items_of_Nahal_Mishmar

Six bronze stamps (a-b) circular with pin-wheel design recalling a svastika (c) square with heart-shaped pattern; broken lug on the back (d-f) broken with radiating spokes; one with broken lug. British Museum No.1880.3710.a-f

Curator's comments: IM.Metal.154. C. Fabrègues: Together with 1880.3710.b-c, the object belongs to the large class of compartmented seals. Such partitioned seals are characteristic of the Bactria-Margiana Archaeological Complex (BMAC, also known as the Oxus Civilization), the modern archaeological designation for a Bronze Age culture located along the upper Amu Darya (Oxus River) in present-day Turkmenistan, Afghanistan, southern Uzbekistan and western Tajikistan. The BMAC may have extended as far as southern Afghanistan and Baluchistan, which have also yielded artefacts typical of the culture. 'Six bronze stamps for impressing designs'. That is, these objects could also have served as seals to impress on objects produced for trade by metalworking artisans. Compartmented seals have been found in large numbers in these areas, both from clandestine diggings in the 1970s (Pottier 1984, Tosi 1988, fig.11, Salvatori 1988) and from scientific excavations. Known sites where examples have been excavated are: Namazga on the banks of the Murghab river (Masson and Sarianidi 1972) Togolok (Sarianidi 1990) and Gonur Tepe in Margiana (Sarianidi 1993, 2002), Dashly Tepe (Masson and Sarianidi 1972) and Mundigak (Casal 1961) in Afghanistan, Dabar Kot, Rana Gundai and Shahi Tump (Amiet 1977, p.117), and the Mehrgarh-Sibri complex (Sarianidi 1993, p.37) in Baluchistan. These seals depict geometrical motifs, like 1880.3710.a–c, and also floral motifs, crosses, animals such as goats, snakes and scorpions, birds (primarily eagles with spread wings), human figures and fantastic dragons. 1880.3710.a, c closely resemble some examples from plundered tombs in Bactria, now in the Louvre Museum (Amiet 2002, p.168, fig.13.h, l) and 1880.3710.c an example said to come from southern Bactria, now in a private collection (Salvatori 1988, p.183, fig.49, bottom right). Impressions of such seals have been found on pottery. Scholars disagree about their use. It has been suggested that they were used for administrative control of trade and production (Hiebert 1994, p. 380); were related to a well organised trade system which involved transporting and transacting goods over long distances (Salvatori 1988, p.163); were symbols of power and property, or, since a large number have similar images, they may have served as amulets protecting their owners from evil rather than as symbols of ownership (Sarianidi 2002, p.41). Compartmented seals have been variously dated to the end of the 3rd/beginning of the 2nd millennium (Amiet 1977, p.119, Salvatori 1988), or to the first half of the 2nd millennium BC (Tosi 1988, p.123, Sarianidi 1993, p.36). According to Amiet (1977, p.117, 1988, pp.166, 169), they originated in Iranian Sistan: at Shar-i-Sokhta their development can be charted throughout the 3rd millennium BC from steatite prototypes and it is only here and at Shahdad, on the other side of the Lut desert in the Kerman region, that they are known to have been used as marks on pottery (Hakemi and Sajjadi 1988, pp.145, 150). Sarianidi considers this a purely local invention (2002, p.41).The Begram seals add to the number of examples already available, provide an exact provenance for some varieties and evidence that the Begram plain had interaction with the BMAC."

http://www.britishmuseum.org/research/collection_online/collection_object_details/collection_image_gallery.aspx?assetId=297337001&objectId=179600&partId=1#more-views

Leopard weight. Shahi Tump. H.16.7cm; dia.13.5cm; base dia 6cm; handle on top.  Seashells inlays on frieze. The pair of leopard and ibex is shown twice, separated by stylized flies.

"The “Leopards Weight” (Balochistan, late fourth or early third millennium B.C.) is one of the best examples of these developments: the lost-wax copper jacket, with its opened hollow shape, constitutes an extraordinary technical achievement.(Mille, B., Bourgarit, D., and Besenval, R. 2005. 'Metallurgical study of the 'Leopards weight' from Shahi-Tump (Pakistan)', in C. Jarrige and V. Lefevre, eds., South Asian Archaeology 2001, Editions Recherches sur les Civilisations, Paris: 237-44) True hollow casting does not appear until the third millennium B.C., as illustrated by the manufacture of statuettes, including the Nausharo bull figurine (Balochistan, 2300–2100 B.C.), or those from BMAC sites in Central Asia (based upon analyses of items in the Louvre collections). The birth of the lost-wax casting process can also be paralleled with the first emergence of alloying in South Asia, as many of these early lost-wax cast artefacts were made of a copper-lead alloy (c. 10–40 wt% Pb and up to 4 wt% As). Significantly, it seems that the copper-lead alloy was solely dedicated to artefacts made using the lost-wax technique, a choice no doubt driven by the advantageous casting properties of such an alloy." (Mille, Benoit, On the origin of lost-wax casting and alloying in the Indo-Iranian world, in: Lloyd Weeks, 2007, The 2007 Early Iranian metallurgy workshop at the University of Nottingham)  

Novel imaging approach reveals how ancient amulet was made

November 15, 2016, CNRS

At 6000 years old, this copper amulet is the earliest lost-wax cast object known. Now, researchers have finally discovered how it was made, using a novel UV-visible photoluminescence spectral imaging approach. All the parameters of elaboration process, such as the purity of the copper, and melting and solidification temperatures, are now accurately known. This work has enabled the scientists to solve the mystery of the invention of lost-wax casting, a technique that led to art foundry. Resulting from a collaboration1 between researchers from the CNRS, the French Ministry of Culture and Communication and the SOLEIL synchrotron, the work is published on 15 november 2016 in the journal Nature Communications.

The researchers examined a copper amulet, discovered in the 1980s at a site that was occupied 6,000 years ago and had been a focal point for innovation since Neolithic times: Mehrgarh, in today's Pakistan. The shape of the object shows that it was designed using the earliest known precision casting technique, lost-wax casting (still in use today). The process begins with a model formed in a low melting point material such as beeswax. The model is covered with clay, which is heated to remove the wax and then baked. The mould is filled with molten metal and then broken to release the metal object. This was all that was known about the process used to make the copper amulet until it was subjected to a novel photoluminescence approach, which revealed that it had an unexpected internal structure.

Although the amulet today consists mainly of copper oxide (cuprite), it emits a non-uniform response under UV-visible illumination. Between the dendrites formed during initial solidification of the molten metal, the researchers found rods that were undetectable using all other approaches tested. The shape and arrangement of the rods enabled the team to reconstruct the process used to make the amulet with an unprecedented level of detail for such a corroded object.

6,000 years ago, following high-temperature solidification of the copper forming it, the amulet was made up of a pure copper matrix dotted with cuprite rods, resulting from the oxidizing conditions of the melt. Over time, the copper matrix also corroded to cuprite. The contrast observed using photoluminescence results from a difference in crystal defects between the two cuprites present: there are oxygen atoms missing in the cuprite of the rods, a defect that is not present in the cuprite formed by corrosion.

This innovative imaging technique, with high resolution and a very wide field of view, made it possible to identify the ore used (extremely pure copper), the quantity of oxygen absorbed by the molten metal, and even the melting and solidification temperatures (around 1072 °C). The discovery illustrates the potential of this new analytical approach, which can be applied to the study of an extremely wide range of complex systems, such as semiconducting materials, composites and, of course, archaeological objects.

https://phys.org/news/2016-11-imaging-approach-reveals-ancient-amulet.html