Identification guide · Minerals
How to Identify Olivine
Olivine typically appears as small, rounded, glassy grains or granular masses in dark volcanic rock, ranging in color from olive green to yellow-green, with a vitreous luster and a white to colorless streak. Its hardness of 6.5 to 7 and conchoidal fracture, combined with a lack of visible cleavage, distinguish it from softer green minerals like epidote or chlorite that can occur in similar settings. Olivine is commonly confused with peridot only in gem form, but in rock specimens it is more often mistaken for green pyroxene, which shows distinct cleavage planes that olivine lacks.
Olivine identification checklist
| Color | Olive green, Yellowish green, Brown | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Transparent to translucent | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 6.5–7 | It scratches glass and a steel knife and cannot be scratched by a steel file. |
| Streak | White | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Poor, two directions | |
| Fracture | Conchoidal | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 3.3–4.3 | Heavier than it looks (specific gravity about 3.8). |
| Crystal system | Orthorhombic |
Extra tests for Olivine
Glass check. Olivine shares a glassy luster and conchoidal fracture with man-made glass. Glass sits near Mohs 5.5 and often contains round gas bubbles, so a hardness test and a hand lens separate them.
Olivine look-alikes and how to tell them apart
Both sit near Mohs 6.5–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Olivine vs Forsterite →
Both sit near Mohs 6.5–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Olivine vs Peridot →
Both sit near Mohs 6.5–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Olivine vs Andradite →
Both sit near Mohs 6.5–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
Olivine identification FAQ
How can you tell if a rock is Olivine?
Check the color (olive green, yellowish green, and brown), the vitreous luster, a Mohs hardness of 6.5–7 and a white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Olivine?
Olivine has a Mohs hardness of 6.5–7. It scratches glass and a steel knife and cannot be scratched by a steel file.
What is the difference between Olivine and Forsterite?
Olivine (Mohs 6.5–7, vitreous luster) and Forsterite (Mohs 6.5–7, vitreous luster) look alike, but hardness, streak and heft usually separate them. See the full Olivine vs Forsterite comparison for a side-by-side table.
Is Olivine worth anything?
Entry-level Olivine specimens sell for around $2, typical collector pieces about $20, and premium examples $150 or more depending on size, quality and locality.
What color is Olivine?
Olivine is most often olive green, yellowish green, and brown. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
