Green Quartz
Silicon dioxide (SiO2)
A green variety of macrocrystalline quartz, usually the heat- or radiation-altered prasiolite, prized for its soft mint hue.
- Mohs hardness
- 7
- Color
- pale to medium leek or mint green
- Type
- crystal
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Overview
Green quartz is a general name for green-colored macrocrystalline quartz. The most common gem form is prasiolite, sometimes marketed misleadingly as green amethyst, which has a pale leek to mint green color.
Most prasiolite on the market is produced by heat-treating or irradiating certain amethyst or yellowish quartz, since naturally green quartz is rare. The color is usually subtle and even.
Like all quartz it is hard, durable, and clear to translucent, making it a pleasant and affordable green gemstone.
Formation & geology
Quartz itself crystallizes from silica-rich solutions in igneous, metamorphic, and hydrothermal settings, growing the familiar hexagonal prisms. The green color in prasiolite arises from iron in the crystal structure altered to a green-producing state.
Most commercial green quartz is created by heating amethyst (often from specific Brazilian deposits) at controlled temperatures, or by irradiation, which shifts the iron coloration from purple to green. Natural prasiolite is found only at a few localities, such as Brazil and Poland.
Naturally green quartz colored by chlorite or other mineral inclusions also occurs but is distinct from prasiolite.
How to identify it
Look for transparent to translucent quartz with a soft, even green color, vitreous luster, conchoidal fracture, hardness 7, and no cleavage. It has a white streak and lacks the doubling or higher dispersion of other green gems.
Distinguish prasiolite from peridot (higher birefringence, oilier green), green fluorite (much softer at 4, with cleavage), and green tourmaline (often more saturated, pleochroic). A hardness test rules out fluorite immediately.
Most green quartz is treated; uniform pale mint color is typical of heat-treated prasiolite.
Uses & significance
Green quartz is faceted into affordable gemstones for rings, pendants, and earrings, valued for its clean clarity and gentle green at low cost. Prasiolite is the usual jewelry form.
Quartz in general also has many industrial and electronic uses, but green-colored gem material is purely ornamental. Metaphysically green quartz is associated with the heart, abundance, and emotional renewal, though such claims are not scientific.
Buyers should know most stones are treated, which is standard and stable for the trade.
Frequently asked questions
Is green quartz the same as green amethyst?
Green amethyst is a marketing term for prasiolite, a green quartz usually made by heat-treating amethyst; calling it amethyst is misleading.
Is green quartz natural?
Natural green quartz exists but is rare; most gem material is heat-treated or irradiated amethyst sold as prasiolite.
How hard is green quartz?
It is 7 on the Mohs scale, durable enough for everyday jewelry.
How can I tell green quartz from peridot?
Peridot shows strong double refraction and an oilier green, while green quartz is single-toned; their hardness is similar, so birefringence is the best test.
Green Quartz guides
In-depth guides for identifying, valuing, and understanding Green Quartz.
Green Quartz identified by the community
Real specimens identified with Rock Identifier.
