Comparison · Minerals
Aegirine vs Diopside
Aegirine and Diopside are easy to confuse because both are minerals. Both sit near Mohs 6–6.5, 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 Aegirine and Diopside
- Both sit near Mohs 6–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Aegirine leaves a pale green to grayish yellow streak on unglazed porcelain, Diopside leaves white.
- Hold a thin edge to the light: Aegirine is Translucent to opaque, Diopside is Transparent to translucent.
- They overlap in green and black, but Aegirine also comes in brown and Diopside also comes in white, gray, blue, purple, and multicolored.
Aegirine vs Diopside properties
| Property | Aegirine | Diopside |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 6–6.5 | 5.5–6.5 |
| Luster | Vitreous | Vitreous |
| Streak | Pale green to grayish yellow | White |
| Transparency | Translucent to opaque | Transparent to translucent |
| Specific gravity | 3.4–3.6 | 3.2–3.3 |
| Crystal system | Monoclinic | Monoclinic |
| Common colors | Dark green, Black, Brown-green | 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 Aegirine and Diopside trade in a similar range, around $20.
About Aegirine
Aegirine is a sodium iron silicate belonging to the pyroxene group, with the formula NaFeSi2O6. It crystallizes in the monoclinic system, typically forming slender, wedge-tipped prisms in alkaline igneous rocks. Its dark green to black color and glassy luster distinguish it from other common pyroxenes.
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.
Aegirine vs Diopside FAQ
Is Aegirine the same as Diopside?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 6–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Aegirine from Diopside?
Both sit near Mohs 6–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Aegirine leaves a pale green to grayish yellow streak on unglazed porcelain, Diopside leaves white. Hold a thin edge to the light: Aegirine is Translucent to opaque, Diopside is Transparent to translucent.
Which is harder, Aegirine or Diopside?
They are about equally hard, both near Mohs 6–6.5.
Which is more valuable, Aegirine or Diopside?
Typical specimens of Aegirine and Diopside trade in a similar range, around $20.
