Identification guide · Sulfide Minerals
How to Identify Sphalerite
Sphalerite is usually brown, black, and yellow with a resinous luster and is transparent. It has a Mohs hardness of 3.75. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Its streak is brownish white to pale yellow. It is most often confused with Amber, Fluorite, and Mimetite; the tests below separate them.
Sphalerite identification checklist
| Color | Brown, Black, Yellow, Red, Green | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Resinous | Compare a fresh surface with glass and metal; this luster is softer than either. |
| Transparency | Transparent | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 3.75 | A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. |
| Streak | Brownish white to pale yellow | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Perfect dodecahedral | |
| Fracture | Conchoidal | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 4.05 | Heavier than it looks (specific gravity about 4.05). |
| Crystal system | Cubic |
Sphalerite look-alikes and how to tell them apart
Sphalerite is harder (Mohs 3.75) than Amber (Mohs 2.5), so Sphalerite will scratch Amber and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Sphalerite vs Amber →
Both sit near Mohs 3.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Sphalerite vs Fluorite →
Both sit near Mohs 3.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Sphalerite vs Mimetite →
Sphalerite is harder (Mohs 3.75) than Phlogopite (Mohs 2.75), so Sphalerite will scratch Phlogopite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
Field tips
- Look for resinous to adamantine luster, perfect cleavage in six directions, and a pale brownish to yellow streak.
- Color varies widely with iron content, so rely on luster, cleavage, and streak rather than color alone.
- Moderate hardness near 3.5 to 4 and high density help confirm an identification.
Sphalerite identification FAQ
How can you tell if a rock is Sphalerite?
Check the color (brown, black, yellow, and red), the resinous luster, a Mohs hardness of 3.75 and a brownish white to pale yellow streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Sphalerite?
Sphalerite has a Mohs hardness of 3.75. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
What is the difference between Sphalerite and Amber?
Sphalerite (Mohs 3.75, resinous luster) and Amber (Mohs 2.5, resinous luster) look alike, but hardness, streak and heft usually separate them. See the full Sphalerite vs Amber comparison for a side-by-side table.
Is Sphalerite worth anything?
Entry-level Sphalerite specimens sell for around $5, typical collector pieces about $70, and premium examples $600 or more depending on size, quality and locality.
What color is Sphalerite?
Sphalerite is most often brown, black, yellow, and red. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
