Comparison · Sulfide Minerals
Orpiment vs Realgar
Orpiment and Realgar are easy to confuse because both are sulfide minerals. Both sit near Mohs 1.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Orpiment and Realgar
- Both sit near Mohs 1.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Orpiment leaves a pale lemon yellow streak on unglazed porcelain, Realgar leaves orange-red to yellow-orange.
- They overlap in orange, but Orpiment also comes in yellow and brown and Realgar also comes in red.
Orpiment vs Realgar properties
| Property | Orpiment | Realgar |
|---|---|---|
| Type | Sulfide Minerals | Sulfide Minerals |
| Mohs hardness | 1.75 | 1.75 |
| Luster | resinous | resinous |
| Streak | Pale lemon yellow | Orange-red to yellow-orange |
| Transparency | translucent | translucent |
| Specific gravity | 3.49 | 3.56 |
| Crystal system | monoclinic | monoclinic |
| Common colors | Lemon yellow, Golden yellow, Orange-yellow, Brownish yellow | Red, Orange-red, Orange |
| Rarity | uncommon | uncommon |
| Typical specimen value | $10–$400+ | $10–$450+ |
Which is more valuable?
Realgar is usually the more valuable of the two: a typical collector specimen runs about $70 against $60 for Orpiment, and premium Realgar can reach $450 or more.
About Orpiment
Orpiment is a soft arsenic sulfide mineral famous for its brilliant lemon to golden-yellow color and resinous luster. It forms in low-temperature veins and hot spring deposits, commonly alongside red-orange realgar.
About Realgar
Realgar is an arsenic sulfide mineral famous for its brilliant orange-red to red color and resinous luster. It forms soft, often translucent crystals and granular crusts, and slowly breaks down to a powder when exposed to light.
Orpiment vs Realgar FAQ
Is Orpiment the same as Realgar?
No. Both are sulfide minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 1.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Orpiment from Realgar?
Both sit near Mohs 1.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Orpiment leaves a pale lemon yellow streak on unglazed porcelain, Realgar leaves orange-red to yellow-orange. They overlap in orange, but Orpiment also comes in yellow and brown and Realgar also comes in red.
Which is harder, Orpiment or Realgar?
They are about equally hard, both near Mohs 1.75.
Which is more valuable, Orpiment or Realgar?
Realgar is usually the more valuable of the two: a typical collector specimen runs about $70 against $60 for Orpiment, and premium Realgar can reach $450 or more.
