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Rock Crystal Quartz

If pyrite is known as “fools’s gold,” then rock crystal—the clear colorless variety of quartz—could be called “fool’s diamond.” Certainly, rock crystal fooled experts for a very long time. And explaining the differences between rock crystal and diamond kept scientists of antiquity busy. Here’s what they wound up saying and the gem world kept believing—that is, until the dawn of modern chemical analysis.

According to Ann and Si Frazier in the April 1992 Lapidary Journal, the ancients divided colorless gems into two types: ripe and unripe. You can guess which was which. Ripe gems were diamonds and unripe gems were crystal quartzes. The distinction was based primarily on origin. Had the latter, it was theorized, grown in the warmer climes of the East, they would have “ripened” into diamonds. But having grown in the harsh, cold climes of the West, quartzes were victims of arrested development.

Actually, unripe gems weren’t just quartzes—just as ripe gems weren’t always diamonds. The two categories encompassed a slew of species, including topaz, corundum and beryl, that were classified as either adamas (indestructible) or krystallos (ice-like), depending on origin. Indeed, it was widely believed—even by the likes of such eminent ancients as Theophrastus (an Athenian naturalist who wrote the earliest-known treatise on gems, “A History of Stones,” circa 315 B.C.) and Pliny the Elder (the Roman follow-up who wrote the second-oldest study on gems circa 50 A.D.)—that crystal was ice frozen so solid it couldn’t thaw. Hard as crystal was, it still was no match for adamas.

Thus rock crystal as a gem was the poor man’s diamond. But as a mineral, it was the rich man’s glass, used during the Middle Ages and the Renaissance to make vessels and containers often “so beautifully engraved with pictured figures as to be transformed into veritable works of art,” wrote gemologist Max Bauer in his 1896 book, “Precious Stones.” As glass-making came into its own, he continued, “the art of working rock-crystal became forgotten, for it was soon found that vessels equally transparent and finely finished could be made in glass with much less labor.”

But, excepting amethyst, rock crystal was the most important quartz family member for considerably more than a millennium. This stature is confirmed by visits to the Prado Museum in Madrid, Spain, and the Rijks Museum in Amsterdam, the Netherlands, “where,” says Si Frazier, “entire galleries are devoted to masterpieces of Renaissance art in the form of carved and engraved Alpine rock crystal.” But if Europe isn’t in your travel plans, visit the annual Tucson Gem Show where displays of works by a new generation of gem carvers, including Susan Allen, Tom McPhee and Howard Fiedler, suggest the greatest resurgence of rock crystal artisanship in centuries.


Anyone familiar with the history of diamond production would know that many so-called diamonds worn in the West until the discovery of Brazil’s diamond deposits in 1725 were likely rock crystal quartz from the Alps. Only the flood of stones from South Africa’s mammoth diamond mines in the early 1870s finally began to alleviate the need for quartz as a substitute.

Until then, rock crystal had served as one of the better and most readily available diamond stand-ins—so effective as such that when the Hapsburgs of Austria ruled Belgium between 1477 and 1792 they outlawed mining of rock crystal. No wonder, then, that some experts call rock crystal “quartz-diamond.” The most famous of these quartz-diamonds is rhinestone. “Originally,” notes Frazier, “they were called ‘Rhine Diamonds’ because they were cut from pieces of Alps rock crystal washed down the Rhine River.”

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Rock Crystal Quartz