Comparison · Minerals vs Silicate Minerals
Actinolite vs Tremolite
Actinolite and Tremolite are easy to confuse. Both sit near Mohs 5–6, 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 Actinolite and Tremolite
- Both sit near Mohs 5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Hold a thin edge to the light: Actinolite is Translucent to opaque, Tremolite is translucent.
- They overlap in green and gray, but Actinolite also comes in black and Tremolite also comes in white and pink.
- Well-formed crystals give it away: Actinolite is Monoclinic, Tremolite is monoclinic.
Actinolite vs Tremolite properties
| Property | Actinolite | Tremolite |
|---|---|---|
| Type | Minerals | Silicate Minerals |
| Mohs hardness | 5–6 | 5.5 |
| Luster | Vitreous to silky | vitreous |
| Streak | White | White |
| Transparency | Translucent to opaque | translucent |
| Specific gravity | 3.0–3.2 | 3 |
| Crystal system | Monoclinic | monoclinic |
| Common colors | Green, Dark green, Grayish green, Black | White, Gray, Green, Pink |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $8–$250+ |
Which is more valuable?
Tremolite is usually the more valuable of the two: a typical collector specimen runs about $40 against $20 for Actinolite, and premium Tremolite can reach $250 or more.
About Actinolite
Actinolite is a calcium-magnesium-iron amphibole with the formula Ca2(Mg,Fe)5Si8O22(OH)2, part of the tremolite-actinolite-ferro-actinolite solid solution series. Its green color comes directly from iron substituting for magnesium within the crystal structure, and it typically grows as elongated, bladed to fibrous crystals. The mineral is best known to rockhounds as a key component of nephrite jade.
About Tremolite
Tremolite is a calcium magnesium amphibole that occurs as bladed, columnar, or fibrous crystals, typically white to gray but ranging to green or pink. It is a common metamorphic mineral and the magnesium end-member of the tremolite-actinolite series.
Actinolite vs Tremolite FAQ
Is Actinolite the same as Tremolite?
No. Actinolite is a mineral while Tremolite is a silicate mineral. Both sit near Mohs 5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Actinolite from Tremolite?
Both sit near Mohs 5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hold a thin edge to the light: Actinolite is Translucent to opaque, Tremolite is translucent. They overlap in green and gray, but Actinolite also comes in black and Tremolite also comes in white and pink.
Which is harder, Actinolite or Tremolite?
They are about equally hard, both near Mohs 5–6.
Which is more valuable, Actinolite or Tremolite?
Tremolite is usually the more valuable of the two: a typical collector specimen runs about $40 against $20 for Actinolite, and premium Tremolite can reach $250 or more.
