Under a polariscope, quartz stones (including synthetic quartz) are the only minerals that produce a bullseye interference figure. Optic Character & Sign: Doubly-refractive (DR) Uniaxial Positive (U+)

Pleochroism: Only present in rose quartz (strong), amethyst (weak), citrine (weak), ametrine (weak) & prasiolite (weak)īirefringence: Macro - 0.009 Micro - 0.004ĭispersion (Fire): Macro - 0.013 Micro - 0.008 Luster: Macro - Vitreous (glass-like) Micro - Greasy, waxy, or sub-vitreous Here’s a complete breakdown of the chemical properties of quartz stones including the macrocrystalline and microcrystalline differences:Ĭhemical Composition: SiO2 (silicon dioxide silica)Ĭrystal System: Trigonal (hexagonal prisms) Some traits are consistent across all quartzes: chemical composition, crystal system, cleavage, fracture. Known for its popular green variety (from fuchsite mica) and metallic glittering surface ( aventurescence).Īventurine shouldn’t be confused with sunstone, sometimes called “aventurine feldspar.”īefore we get into each quartz, what characteristics do all types of quartz share? Quartz Specifications May have brown, yellow, red, and white hues.Īventurine: Often treated as a mineral but actually a translucent quartz rock or quartzite variety composed of chalcedony and often feldspar. Quartzite: A metamorphic rock composed of at least 80 percent quartz, usually white, gray, and/or shades of red.Ĭhert: An opaque white, gray, tan, or pink sedimentary rock mostly composed of microcrystalline quartz with lots of tiny water or air inclusions.įlint: A nearly opaque, dark-colored type of chert, colored by carbon-rich inclusions. Some outliers are:ĭruzy Quartz: A glittering layer of many tiny quartz crystals (usually gray) atop a larger crystal, often found inside geodes. Not every type of quartz stone neatly falls under either category. Pictured above: Druzy quartz Unique Quartz Varieties

In a nutshell: Macrocrystalline quartz gems are generally called “quartz” and microcrystalline quartz gems are generally called “chalcedony.” Their crystals are tiny grains (only visible under a microscope) tightly compacted together.Īdditionally, most microcrystalline quartzes have small amounts (1-20 percent) of moganite, a hydrated silica, which can transform into quartz over time. Microcrystalline (or cryptocrystalline) quartz generally refers to gems in the “chalcedony” family. If you hear “quartz variety,” it’s usually macrocrystalline. Macrocrystalline quartz stones have larger, individual crystals that you can see without magnification. When categorizing the dozens of quartz varieties, the main types (or families) of quartz are macrocrystalline and microcrystalline.

By the end, you’ll be able to start identifying different types of quartz gemstones and become a savvy quartz shopper!įirst, let’s go over the basics: what are the main types of quartz? Today, we’ll go over quartz types, characteristics, treatments, synthetics, and inclusions. Ever heard of amethyst, rose quartz, or agate? They’re all types of quartz crystals!īoth as a mineral and a gemstone, quartz boasts tons of impressive properties, including producing accurate vibration frequencies, conducting electricity, and being the “Master Healer” of all healing crystals.īut which gems are quartz? Glad you asked! Quartz (silica) is one of Earth’s most abundant minerals and the base for many gemstone favorites.

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