วัสดุคาร์เนเลียนCarnelian

Carnelian is one of the first stones anybody strung. Red chalcedony was worked into beads in the Early Neolithic in Bulgaria, and the Varna Chalcolithic necropolis, middle of the fifth millennium BCE, gives the first faceted carnelian beads — thirty-two facets, sixteen a side. At Mehrgarh in the fourth and fifth millennia BCE a bow drill was already going through it. The Indus Valley Civilisation made etched carnelian beads through the third millennium BCE, and the stone reached Bronze Age Knossos by about 1800 BCE.

What the stone was asked to carry changed with who cut it. Sard went into Assyrian cylinder seals, into Egyptian and Phoenician scarabs, into early Greek and Etruscan gems. Rome used carnelian for the engraved gems of signet rings, the seal a letter was closed with. The Hebrew odem, first stone of the High Priest's breastplate, was a red stone — probably sard, possibly red jasper.

In the Islamic world the stone's own biography is the argument. Carnelian, 'aqiq, is often favoured because it was taken as the stone of Muhammad, who was said to have worn a carnelian seal set in silver on the little finger of his right hand. Writers on Islamic amulets set out the reasoning plainly: the protective value claimed for a material rests on its natural rarity, its monetary value and its symbolic implications. Carnelian's reddish translucency is read as blood, and the reading is anchored to the clot of congealed blood of Qur'an 96:2. Set beside jade, the pair is read as fertility and embryogenesis.

Inference — carnelian is cut, never moulded, and that is the whole of its class position on a museum tray. The same wedjat eye that came out of a mould in faience by the thousand had to be ground from this stone one at a time. Where a drawer holds both, the stone ones cost more to make, and the tray is a price list as much as a typology.

Still cut for beads and seal rings, and still sold as 'aqiq across West and South Asia. The mineral literature names Yanacodo in Peru and Ratnapura in Sri Lanka among significant localities, with the stone also found in Indonesia, Brazil, India, Iran, Siberia and Germany.