Comparison · Minerals
Augite vs Diopside
Augite and Diopside are easy to confuse because both are minerals. Both sit near Mohs 5.5–6, 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 Augite and Diopside
- Both sit near Mohs 5.5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Augite leaves a grayish green to colorless streak on unglazed porcelain, Diopside leaves white.
- Hold a thin edge to the light: Augite is Translucent to opaque, Diopside is Transparent to translucent.
- They overlap in black and green, but Augite also comes in brown and Diopside also comes in white, gray, blue, purple, and multicolored.
Augite vs Diopside properties
| Property | Augite | Diopside |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 5.5–6 | 5.5–6.5 |
| Luster | Vitreous to resinous | Vitreous |
| Streak | Grayish green to colorless | White |
| Transparency | Translucent to opaque | Transparent to translucent |
| Specific gravity | 3.2–3.6 | 3.2–3.3 |
| Crystal system | Monoclinic | Monoclinic |
| Common colors | Black, Dark green, Brown | Light to dark green, White, Gray, Blue-violet (violane), Black (chromian varieties) |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Augite and Diopside trade in a similar range, around $20.
About Augite
Augite is a common rock-forming pyroxene, a calcium-magnesium-iron silicate with the general formula (Ca,Mg,Fe)2Si2O6, and one of the most abundant dark minerals in basalt and gabbro. It crystallizes in the monoclinic system and typically appears as stubby black to greenish-black prisms with a characteristic near-right-angle cleavage. Augite is a rock-forming mineral rather than a gem material, valued mainly by collectors for its well-formed crystals.
About Diopside
Diopside is a calcium magnesium silicate pyroxene mineral, CaMgSi2O6, common in metamorphosed limestones and mafic to ultramafic igneous rocks. It typically forms stubby prismatic crystals with a nearly square cross-section, a hallmark of the pyroxene group's characteristic cleavage angles. Diopside's color ranges from colorless to deep green depending on iron and chromium content, and chromium-rich varieties are prized as gem material.
Augite vs Diopside FAQ
Is Augite the same as Diopside?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 5.5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Augite from Diopside?
Both sit near Mohs 5.5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Augite leaves a grayish green to colorless streak on unglazed porcelain, Diopside leaves white. Hold a thin edge to the light: Augite is Translucent to opaque, Diopside is Transparent to translucent.
Which is harder, Augite or Diopside?
They are about equally hard, both near Mohs 5.5–6.
Which is more valuable, Augite or Diopside?
Typical specimens of Augite and Diopside trade in a similar range, around $20.
