Quartz is one of the most common crystal minerals on Earth, and offers a bewildering array of varieties and names.

Quartz varieties are commonly separated into two groups based upon the size of the individual grains or crystals; Macrocrystalline Quartz, in which individual crystals are visible to the unaided eye, and Cryptocrystalline Quartz, in which crystals are only visible under high magnification.

Gemstone Quartz varieties include, but are not limited to, Agate, Amethyst, Ametrine, Bloodstone, Carnelian, Chrysoprase, Citrine, Jasper, Rose Quartz, and Smoky Quartz.

Birthstone Month:
Please refer to specific Quartz variety for information regarding birthstone months.

Zodiac:
Please refer to specific Quartz variety for information regarding zodiac signs.

Chemical Symbol:
SiO2

Chemical Make-up:
Quartz is a Silicon Dioxide.

History & Lore:
There is not 100% agreement regarding the exact origins of the name Quartz, but the two most widely accepted opinions are that the word Quartz is derived from the Greek 'krystallos', meaning “ice”, or the German 'quarz'.

Some of the earliest primitive tools fashioned by man some 2.5 million years ago, and discovered in the Omo valley in Ethiopia were made of Quartz. It is believed that Quartz was used because of its hardness and isotropic brittleness that made the fashioning of the tools relatively easy.

Chipped flint projectile points used for fire-making have been found on Mousterian sites in western Europe that date back around 40,000 years.

In addition to its use in tool-making, certain varieties of Quartz were used for divination. Spherical Quartz rock crystals were often shaped into crystal balls and used for disease diagnosis and awareness of events occurring in distant places.

Today, Quartz is not only used for gemstone purposes, but also as a raw chemical ingredient in the manufacturing of abrasives, cements, concrete, porcelain, glass, and many other industrial materials.

Because of its piezoelectric and pyroelectric properties, Quartz is commonly used in the production of watches, clocks, computers, and radios.

Bi-Colored Quartz gemstones are believed to offer the metaphysical properties of both the gemstones exhibited. Please refer to specific Bi-Colored Quartz variety for further information.

Availability:
Bi-Colored Quartz rarely occurs naturally and most of the Bi-Colored Quartz found on the market today has been enhanced by a heat-treatment process. For Bi-Colored Quartz to occur naturally, the impurities in the quartz have to be affected in different ways. For example, both sides of the stone must be subjected to two slightly different temperatures during the crystallization process of the Quartz for Bi-Colored Quartz to form.

Sources:
Quartz deposits occur worldwide.

Evaluation:
Quartz is rated at 6.5 to 7 on the Moh's Scale of Hardness and besides for all of its practical uses, Quartz is greatly important to the gem trade, accounting for a vast, diverse population of gemstones that are for the most part suitable for all jewelry applications.

Quartz crystals of different colors can form together to create beautiful bi-colored stones. These can be part Citrine and Smoky Quartz, Amethyst and Colorless Quartz, or the increasingly popular Ametrine. Ametrine combines the appeal of both the violet-purple Amethyst and the yellow-orange Citrine in one bi-colored gemstone. Ametrine gemstones can be found displaying an equal share of the Amethyst and Citrine as well as a blended color affect, displaying attractive shades of rosy gold and mauve.

The most important aspects to consider when viewing a Bi-Colored Quartz is the depth and intensity of the colors and the distinctiveness of the separation. The creativity of the cut should also be taken into account.

Common Cuts:
Bi-Colored Quartz is generally found faceted in a rectangular shape displaying equal amounts of the two colors. It is occasionally designed in a checkerboard pattern of facets to increase the light reflection.

Routine Enhancements:
Most of the Bi-Colored Quartz found on the market today has actually been enhanced by a heat-treatment process.

Care & Cleaning:
Quartz varieties are generally best cleaned using warm soapy water and a soft brush. As with most gemstones, Quartz should be kept away from household chemicals and from prolonged exposure to extremes of heat as this can cause damage or permanent changes in coloration. Quartz should be kept in a fabric-lined box away from other jewelry items in order to avoid scratching.