Identification guide · Native Elements
How to Identify Platinum
Platinum is usually silver, gray, and steel gray with a metallic luster and is opaque. It has a Mohs hardness of 4.25. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Its streak is steel gray to silver-white. It is most often confused with Iron, Gold, and Silver; the tests below separate them.
Platinum identification checklist
| Color | Silver, Gray, Steel gray | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Metallic | Turn it under a lamp: a true metallic shine reflects like polished metal and stays opaque at thin edges. |
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 4.25 | A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. |
| Streak | Steel gray to silver-white | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | None | |
| Fracture | Hackly | |
| Specific gravity | 18 | Very heavy, metallic heft (specific gravity about 18). |
| Crystal system | Cubic |
Platinum look-alikes and how to tell them apart
Both sit near Mohs 4.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Platinum vs Iron →
Platinum is harder (Mohs 4.25) than Gold (Mohs 2.5), so Platinum will scratch Gold and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Platinum vs Gold →
Platinum is harder (Mohs 4.25) than Silver (Mohs 2.75), so Platinum will scratch Silver and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Platinum vs Silver →
Chromite is harder (Mohs 5.5) than Platinum (Mohs 4.25), so Chromite will scratch Platinum and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
Field tips
- Look for a silvery to steel-gray metallic color that does not tarnish and unusually high density for its size.
- Native platinum is malleable and lacks cleavage, typically forming grains and nuggets rather than crystals.
- Confirm rare or valuable specimens with provenance, density checks, and qualified testing when needed.
Platinum identification FAQ
How can you tell if a rock is Platinum?
Check the color (silver, gray, and steel gray), the metallic luster, a Mohs hardness of 4.25 and a steel gray to silver-white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Platinum?
Platinum has a Mohs hardness of 4.25. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
What is the difference between Platinum and Iron?
Platinum (Mohs 4.25, metallic luster) and Iron (Mohs 4, metallic luster) look alike, but hardness, streak and heft usually separate them. See the full Platinum vs Iron comparison for a side-by-side table.
Is Platinum worth anything?
Entry-level Platinum specimens sell for around $60, typical collector pieces about $900, and premium examples $8000 or more depending on size, quality and locality.
What color is Platinum?
Platinum is most often silver, gray, and steel gray. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
