Chrysoprase

History and lore

The name joins two Greek words, chrysos, "gold", and prason, "leek", describing a golden or yellowish green. As so often with ancient gem names, it is not certain that the Greek chrysoprasos meant the stone we now call chrysoprase; the word may have covered several golden-green materials. The modern gem, an apple-green chalcedony, is first securely documented in Europe from deposits in Lower Silesia, around Szklary near Ząbkowice Śląskie in present-day Poland, which were worked from the late Middle Ages.

Silesian and Bohemian stones were used lavishly in fourteenth-century Prague. The walls of the Chapel of St Wenceslas in St Vitus Cathedral and the Chapel of the Holy Cross at Karlštejn Castle, both created for the emperor Charles IV, are inlaid with polished semiprecious stones, and chrysoprase is usually listed among them with amethyst, jasper and chalcedony. After Prussia seized Silesia in the 1740s, Frederick the Great became the stone's most famous patron, using it in furnishings at his palace of Sanssouci in Potsdam and in the jewelled gold snuffboxes he collected. The Silesian deposits were largely exhausted by the nineteenth century. Since the 1960s the finest material has come from Queensland, Australia, with further production from Tanzania, Brazil and Kazakhstan.

In the traditions

Chrysoprase has one scriptural moment, but an exalted one: the King James Bible names "chrysoprasus" as the tenth of the twelve foundations of the wall of the heavenly Jerusalem (Revelation 21:20). It does not appear in the High Priest's breastplate of Exodus 28. Medieval commentators who allegorised the foundations assigned each stone to an apostle or a virtue, and the pairings differ from writer to writer. Renaissance magic did not single chrysoprase out, but Agrippa gives green stones generally to Venus, which this entry follows; modern tables accordingly link it with Taurus and Libra, Venus's signs.

Chrysoprase is not on the American birthstone lists. A British jewellers' list usually dated to 1937 offered it as an alternative to emerald for May. Twentieth-century crystal literature describes chrysoprase as a stone of the heart, forgiveness and renewal; these are modern meanings, and scientific studies have not found that crystals heal or alter emotions.

Meaning and symbolism

Chrysoprase is a stone of fresh green: spring, renewal and hope. Its place among the foundations of the city "of pure gold, like unto clear glass" (Revelation 21:18) made it, for Christian readers, part of the imagery of a restored creation. For Frederick the Great and other eighteenth-century collectors it was also a luxury of rarity and taste, a stone that marked a connoisseur.

The mineral

Chrysoprase is translucent chalcedony whose colour comes from tiny particles of nickel-bearing minerals. It forms where nickel-rich rocks such as serpentinite weather deeply in warm climates, releasing silica and nickel that are redeposited together in cracks and cavities. The best stones have an even, intense apple-green colour and good translucency.

With a hardness of 6.5–7, chrysoprase is reasonably durable, but its colour can fade with prolonged heat or strong sunlight, and some pale stones regain colour when kept slightly moist; store it away from heat and sunny windows. Imitations include green-dyed chalcedony or agate, which often shows colour concentrated along bands, green glass, and nephrite or other green stones. The trade name "Australian jade" for chrysoprase is a misnomer (see jade), and "lemon chrysoprase" is usually a nickel-bearing magnesite, a different mineral. Clean with warm soapy water and avoid harsh chemicals.

Sources and further reading

• Revelation 21 — King James Bible, 1611
• Natural History, Book 37 — Pliny the Elder, c. 77 CE
• Three Books of Occult Philosophy — Heinrich Cornelius Agrippa, 1533
• The Curious Lore of Precious Stones — George Frederick Kunz, 1913
• Gems: Their Sources, Descriptions and Identification (6th ed.) — Michael O'Donoghue (ed.), 2006