Rock Crystal Quartz

Diamonds may claim ownership of the nickname "ice," but rock crystal is actually named for that frozen substance. Pliny the Elder called it krystallos—Greek for "ice." It's an appropriate name: Rock crystal quartz does look a lot like ice. But did Pliny actually believe that rock crystal was ice, frozen so hard it would never melt again? Pretty vivid imagination, considering that quartz really isn't that cold to the touch.

Rock crystal, colorless quartz, silicon dioxide—whatever you call it, it's one of the most versatile gem materials ever unearthed. It is used as a gemstone, beautiful in its own right, and also cut to imitate the ultimate colorless gem, diamond. In fact, doubly terminated (i.e., with a classic pyramidal point at both ends of the specimen) rock crystal quartz crystals found in Herkimer, N.Y., have been dubbed "Herkimer diamonds."

Rock crystal has been carved into ornaments such as candlesticks, chessmen and chessboards, eggs, and bowls as well as thousands of other objects of delight. And because it is found in such large crystals, sometimes weighing hundreds of pounds, you can find large sculptures made of rock crystal as well.

Rock crystal has a place in the world of science, too: It has been polished to exact proportions for use as standards in weights and measures. But probably one of the most recognized forms that rock crystal takes on is that of a crystal ball. One of the largest and most perfect crystal balls resides in the Smithsonian's gem and mineral collection, sans fortuneteller.

Rock crystal is used to create timepieces in computers and, of course, watches. It is a piezoelectric mineral, which means that physical pressure causes it to release electricity, and electricity causes it to vibrate. Here's how it works: The watch battery causes the quartz crystal to vibrate. A microprocessor converts that vibration to a much slower electrical pulse. The pulsing current activates a magnet, which switches rapidly back and forth, turning a small pinion that drives the gear train.

Many crystals are believed to have healing properties for various areas of the body, and rock crystal quartz crystals are considered particularly effective. Quartz is said to have the ability to correct a chaotic energy flow—i.e., if you're feeling stressed out, the crystal can balance your energies and revitalize you. As a universal conduit, it can remove negative energy while amplifying, focusing, storing, and transforming other energies.

Rock crystal is colorless, transparent, and has crystal-clear clarity. The specific gravity/density of quartz is listed at 2.70. Compared to a diamond—which has a specific gravity of 3.52—a 1-ct. rock crystal will look 25% larger.

Major sources for the gem material are found in Brazil, Madagascar, China, the United States (Arkansas), and Canada; however, rock crystal is found virtually on every continent.

Today, the phrase "genuine crystal" can mean two different things—rock crystal or leaded glass. However, a few hundred years ago, there was only one genuine crystal, and one of the great examples hangs within the original Chateau de Versailles, official residence for the court of France. Built in the 15th and 16th centuries, the magnificent halls and rooms of Versailles were—and still are—lit by thousands of crystal chandeliers. Each piece of rock crystal quartz was formed and polished by hand by craftsmen in Idar-Oberstein, who today still maintain the original quality of each chandelier, replacing broken crystals with new ones cut to original specifications.

Large synthetic quartz crystals, grown by a hydrothermal process, are produced in enormous quantities to satisfy the industrial demand. Identification is sometimes impossible.

Because both natural and synthetic crystal quartz is so abundant, it can be very cheap. But this also means that for unsuspecting jewelers, synthetic quartz as well as glass can easily be substituted for the real thing, so price alone is no guarantee of authenticity. Always check the merchandise. The cost will ultimately reflect the quality of the material as well as the workmanship employed to create the piece.