Comparison · Minerals vs Sulfide Minerals
Cinnabar vs Realgar
Cinnabar and Realgar are easy to confuse. Both sit near Mohs 2–2.5, 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 Cinnabar and Realgar
- Both sit near Mohs 2–2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Cinnabar leaves a scarlet red streak on unglazed porcelain, Realgar leaves orange-red to yellow-orange.
- Luster is different: Cinnabar is adamantine to dull/earthy while Realgar is resinous.
- Cinnabar feels noticeably heavier for its size (specific gravity 8.0–8.2 versus 3.56 for Realgar).
- Hold a thin edge to the light: Cinnabar is Transparent to opaque, Realgar is translucent.
- They overlap in red, but Cinnabar also comes in brown and gray and Realgar also comes in orange.
- Well-formed crystals give it away: Cinnabar is Trigonal, Realgar is monoclinic.
Cinnabar vs Realgar properties
| Property | Cinnabar | Realgar |
|---|---|---|
| Type | Minerals | Sulfide Minerals |
| Mohs hardness | 2–2.5 | 1.75 |
| Luster | Adamantine to dull/earthy | resinous |
| Streak | Scarlet red | Orange-red to yellow-orange |
| Transparency | Transparent to opaque | translucent |
| Specific gravity | 8.0–8.2 | 3.56 |
| Crystal system | Trigonal | monoclinic |
| Common colors | Red, Brownish red, Gray where tarnished | Red, Orange-red, Orange |
| Rarity | common | uncommon |
| Typical specimen value | $2–$150+ | $10–$450+ |
Which is more valuable?
Realgar is usually the more valuable of the two: a typical collector specimen runs about $70 against $20 for Cinnabar, and premium Realgar can reach $450 or more.
About Cinnabar
Cinnabar is mercury sulfide, HgS, the principal ore mineral of mercury and one of the most historically significant toxic minerals in human history. It forms a brilliant red to brownish-red mineral typically deposited by low-temperature hydrothermal fluids near volcanic activity and hot springs, often associated with recent or geologically young volcanic terrains. Cinnabar has been mined for millennia both for its metal content and, historically and dangerously, as a pigment source.
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.
Cinnabar vs Realgar FAQ
Is Cinnabar the same as Realgar?
No. Cinnabar is a mineral while Realgar is a sulfide mineral. Both sit near Mohs 2–2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Cinnabar from Realgar?
Both sit near Mohs 2–2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Cinnabar leaves a scarlet red streak on unglazed porcelain, Realgar leaves orange-red to yellow-orange. Luster is different: Cinnabar is adamantine to dull/earthy while Realgar is resinous.
Which is harder, Cinnabar or Realgar?
Cinnabar is harder: Mohs 2–2.5 against Mohs 1.75 for Realgar.
Which is more valuable, Cinnabar or Realgar?
Realgar is usually the more valuable of the two: a typical collector specimen runs about $70 against $20 for Cinnabar, and premium Realgar can reach $450 or more.
