Quartz
| Property | Details |
|---|
| Mineral | Quartz (silicon dioxide) |
| Mohs Hardness | 7 |
| Refractive Index | 1.544 – 1.553 |
| Birthstone | Varieties: February (amethyst), November (citrine) |
| Major Sources | Brazil, Madagascar, USA, Zambia, India |
| Treatments | Heat, irradiation (common for many varieties) |
Overview
Quartz is the second most abundant mineral in Earth’s crust and one of the most diverse gemstone families. While amethyst and citrine are the best-known quartz varieties (each with their own guide on our site), the quartz family encompasses dozens of beautiful gemstones in virtually every color. From the romantic blush of rose quartz to the mysterious depths of smoky quartz, this family offers something for every taste and budget.
Varieties
Rose quartz: Soft pink, translucent to opaque. The stone of unconditional love. Usually cabochon-cut; transparent faceted specimens are rare and valuable. Smoky quartz: Light brown to nearly black. Elegant, understated, and increasingly popular in modern jewelry. Rutilated quartz: Transparent quartz shot through with golden, copper, or silver needle-like inclusions of rutile. Each stone is unique. Prasiolite (green amethyst): Pale green quartz, usually produced by heating amethyst. Rock crystal: Colorless, transparent quartz—used in jewelry and decorative arts for millennia. Milky quartz: White, translucent quartz. Tiger’s eye: Golden-brown with chatoyant bands, a form of fibrous quartz. Aventurine: Green quartz with sparkling inclusions of fuchsite mica.
Quality & Value Factors
Value varies enormously across quartz varieties. Star rose quartz with a sharp, well-defined six-rayed star is the most valuable. Transparent, deeply saturated rose quartz commands a premium over common translucent material. For rutilated quartz, evenly distributed, well-defined golden needles in clear quartz are most desirable. Smoky quartz should be medium brown—too dark appears nearly black and lifeless, while too light lacks character. Overall, quartz offers exceptional value: large, eye-clean gemstones in beautiful colors at a fraction of the cost of rarer stones.
Care & Cleaning
Quartz ranks 7 on the Mohs scale, making it durable enough for most jewelry. Clean with warm soapy water and a soft brush. Ultrasonic cleaners are generally safe for solid quartz varieties but should be avoided for included varieties (rutilated quartz) and dyed or treated material. Important: Amethyst, citrine, and rose quartz can fade with prolonged exposure to direct sunlight or intense heat. Store colored quartz away from windows and remove before extended sun exposure.