Quartz

If you gaze deep into a crystal ball, you will see a versatile gemstone, one of the most popular gems on earth. Beautiful quartz, the 'rock crystal' used in ancient times to make crystal balls and bowls, is today more often seen set in gold jewelry. Different colours and types of chalcedony, from agate to chrysoprase, have grown in popularity with the growing appreciation for carved gemstones and artistic cutting and carving. And unusual specialities like dusty quartz, with its surface covered by tiny sparking crystals, and rutilated quartz, which has a landscape of shining gold needles inside it, are adding variety and nature's artistry to unusual one-of-a-kind jewelry.

Smoky quartz is a brown transparent quartz that is sometimes used for unusual faceted cuts. The commercial market is limited, because there is a rather limited demand for brown gemstones. This variety was sometimes known as smoky topaz in the past, though the term is incorrect and misleading.

Rutilated quartz and tourmalinated quartz

While most varieties of transparent quartz are valued most when they show no inclusions, some are valued chiefly because of them! The most popular of these is known as rutilated quartz. Rutilated quartz is transparent rock crystal with golden needles of rutile arrayed in patterns inside it. Each pattern is different and some are breathtakingly beautiful. The inclusions are sometimes called Venus hair. Less well known is a variety called tourmalinated quartz which, instead of golden rutile, has black or dark green tourmaline crystals.
 

Rose quartz

The pale pink colour of quartz, which can range from transparent to translucent, is known as rose quartz. The colour is a very pale and delicate powder pink. Transparent rose quartz is very rare, and usually so pale that it does not show very much colour at all except in large sizes. Translucent rose quartz is much more readily available, being used for beads, cabochons, carvings, and architectural purposes.

Tiger's eye

Tiger's eye quartz contains brown iron which produces its golden yellow colour. Cabochon cut stones of this variety show the chatoyancy (small ray of light on the surface) that resembles the feline eye of a tiger. The most important deposit is in South Africa, though tiger's eye is also found in Western Australia, Burma (Myanmar), India and California.

Rock crystal

The transparent, colourless variety of quartz is still known as rock crystal. Long ago, people believed that rock crystal was a compact form of ice: in fact 'crystallos' means 'ice'. The best rock crystal has the clarity and shimmer of water. Although colourless quartz is relatively common, large flawless specimens are not, which is why crystal balls these days are made of glass, not quartz. Rock crystal has often been used in jewelry, particularly carved pieces. Many stunning art deco jewelry designs featured the black and white quartz combination of rock crystal and onyx. Colourless quartz crystals have also become popular in jewelry due to the popularity of legends about their powers. Many people believe that wearing quartz crystals benefits their health and spiritual well-being.