Identification guide · Metamorphic Rocks
How to Identify Serpentinite
Serpentinite typically shows mottled shades of green, gray-green, and black, sometimes with a waxy to greasy luster reminiscent of scaly snakeskin, and it leaves a white to pale green streak. Its hardness ranges from about 3 to 5 depending on which serpentine mineral dominates, and it often has a smooth, soapy feel where talc has formed as a byproduct of alteration. It is most often confused with jade, which is considerably harder and tougher, or with soapstone, which is softer and more talc-rich; a hardness test and the characteristic mottled texture usually resolve the distinction.
Serpentinite identification checklist
| Color | Green, Dark green, Yellowish green, Mottled green and black | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Greasy, waxy, silky | Compare a fresh surface with glass and metal; this luster is softer than either. |
| Transparency | Opaque, translucent in thin splinters | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 2.5–4 | A copper coin (Mohs 3.5) scratches it, but a fingernail does not. |
| Streak | White | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Fracture | Conchoidal to splintery | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 2.5–2.6 | Ordinary rock-like heft (specific gravity about 2.55), similar to quartz. |
Serpentinite look-alikes and how to tell them apart
Both sit near Mohs 2.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Serpentinite vs Serpentine →
Greenschist is harder (Mohs 4.5) than Serpentinite (Mohs 2.5–4), so Greenschist will scratch Serpentinite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Serpentinite vs Greenschist →
Both sit near Mohs 2.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Serpentinite vs Phyllite →
Schist is harder (Mohs 2.5–7) than Serpentinite (Mohs 2.5–4), so Schist will scratch Serpentinite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
Serpentinite identification FAQ
How can you tell if a rock is Serpentinite?
Check the color (green, dark green, yellowish green, and mottled green and black), the greasy, waxy, silky luster, a Mohs hardness of 2.5–4 and a white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Serpentinite?
Serpentinite has a Mohs hardness of 2.5–4. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
What is the difference between Serpentinite and Serpentine?
Serpentinite (Mohs 2.5–4, greasy, waxy, silky luster) and Serpentine (Mohs 3.5, greasy luster) look alike, but hardness, streak and heft usually separate them. See the full Serpentinite vs Serpentine comparison for a side-by-side table.
Is Serpentinite worth anything?
Entry-level Serpentinite specimens sell for around $1, typical collector pieces about $10, and premium examples $75 or more depending on size, quality and locality.
What color is Serpentinite?
Serpentinite is most often green, dark green, yellowish green, and mottled green and black. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
