Green Quartz Identification Guide
How to identify green quartz (prasiolite and chrome quartz) by hardness, crystal form, and fracture, and separate it from beryl, peridot, and glass.
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What Green Quartz Looks Like
Green quartz includes prasiolite (a leek-green quartz usually produced by heating or irradiating amethyst), prase (green from actinolite/chlorite inclusions), and chrome-bearing green quartz. Transparent material is a soft, slightly minty or yellowish green with a bright vitreous luster; included types are more translucent. Crystals are hexagonal prisms terminated by rhombohedral faces, the classic quartz shape.
Step-by-Step Field-ID Checklist
- Look for hexagonal prisms with six-sided cross-section and pointed terminations.
- Test hardness: green quartz scratches glass and steel readily (Mohs 7).
- Check fracture: smooth conchoidal fracture, no cleavage.
- Judge the color: prasiolite is usually a pale, even leek-green; very saturated green suggests another mineral or glass.
- Look for inclusions: prase shows fibrous/green mineral inclusions causing the color.
Key Diagnostic Tests
- Mohs hardness: 7
- Streak: white
- Fracture: conchoidal; no cleavage
- Specific gravity: ~2.65
- Optics: uniaxial positive; weak pleochroism
- No acid reaction; non-magnetic
Common Look-Alikes and How to Tell Them Apart
- Green beryl/emerald: Beryl is harder (7.5–8) and forms flat-topped hexagonal prisms; quartz prisms taper to a point. Density is similar but hardness differs.
- Peridot: Softer (6.5–7), much denser (SG ~3.3), strongly doubly refractive with visible facet doubling.
- Green tourmaline: Rounded-triangular cross-section, stronger pleochroism, slightly denser.
- Green glass: Gas bubbles, swirl marks, mold seams, and no true crystal faces; conchoidal fracture is shared, so look for bubbles.
- Fluorite: Softer (4) with octahedral cleavage—quartz has none.
- Prehnite: Botryoidal, slightly softer, with a different luster.
Where Green Quartz Is Found
Natural prasiolite is rare (notably Brazil—Montezuma, and Poland); most commercial prasiolite is heat-treated amethyst from Brazil and Bolivia. Prase and chrome-rich green quartz occur in metamorphic and skarn settings worldwide.
Frequently asked questions
How can you tell if it's real green quartz?
Real green quartz is hard (Mohs 7, scratches glass and steel), forms six-sided prisms with pointed terminations, breaks with conchoidal fracture and no cleavage, and has a white streak; gas bubbles indicate glass.
Is green quartz (prasiolite) natural?
Natural prasiolite exists but is rare; most green quartz on the market is amethyst that has been heat-treated or irradiated to produce the green color.
What does green quartz look like?
It is a transparent to translucent, soft leek-green or minty stone with a bright glassy luster, typically a hexagonal prism, sometimes with green fibrous inclusions in prase.
Green quartz vs green beryl: how do I tell them apart?
Beryl is harder (7.5–8) and forms flat-topped hexagonal prisms, while quartz is hardness 7 and its prisms taper to pointed rhombohedral terminations.
Green quartz vs peridot: how do I tell them apart?
Peridot is denser and softer with obvious doubling of back facets, whereas green quartz is lighter, harder, and shows little to no facet doubling.
Green Quartz identified by the community
Recent Green Quartz specimens identified with Rock Identifier.
