RocksdayAdamite vs Pyromorphite
How to tell them apart
A zinc arsenate forming lime-green crystal sprays that glow vivid green under UV.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
A lead phosphate forming bright green hexagonal barrels.
Photo: Ivar Leidus, CC BY-SA 4.0
Quick tests
- Heft: Pyromorphite feels noticeably heavier for its size (specific gravity 6.5–7.1 vs 4.3–4.5).
Key differences
- Pyromorphite forms hexagonal barrels and is heavier.
Side by side
| Property | Adamite | Pyromorphite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 3.5 | 3.5–4 |
| Luster | Vitreous | Resinous to adamantine |
| Streak | White | White |
| Colors | Yellow, Green, Purple | Green, Yellow, Brown |
| Crystal system | Orthorhombic | Hexagonal |
| Specific gravity | 4.3–4.5 | 6.5–7.1 |
| Formula | Zn₂AsO₄(OH) | Pb₅(PO₄)₃Cl |
| Found in | Ojuela mine, Mapimí, Mexico; Laurium, Greece | Bunker Hill mine, Idaho; Les Farges, France |
Properties that are the same for both are grayed out.
How to identify adamite
- Lime-yellow-green crystals on brown limonite.
- Glows bright green under UV light.
- Soft — a knife scratches it.
Crystal system: Orthorhombic
Full Adamite guide →How to identify pyromorphite
- Grass-green to olive hexagonal prisms, often hollow-ended.
- Very heavy.
- Resinous luster.
Crystal system: Hexagonal
Full Pyromorphite guide →More comparisons
Could you tell them apart from a blurry close-up?
Play today's Rocksday