Comparison · Minerals
Aegirine vs Augite
Aegirine and Augite 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 Augite
- 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, Augite leaves grayish green to colorless.
Aegirine vs Augite properties
| Property | Aegirine | Augite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 6–6.5 | 5.5–6 |
| Luster | Vitreous | Vitreous to resinous |
| Streak | Pale green to grayish yellow | Grayish green to colorless |
| Transparency | Translucent to opaque | Translucent to opaque |
| Specific gravity | 3.4–3.6 | 3.2–3.6 |
| Crystal system | Monoclinic | Monoclinic |
| Common colors | Dark green, Black, Brown-green | Black, Dark green, Brown |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Aegirine and Augite 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 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.
Aegirine vs Augite FAQ
Is Aegirine the same as Augite?
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 Augite?
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, Augite leaves grayish green to colorless.
Which is harder, Aegirine or Augite?
Aegirine is harder: Mohs 6–6.5 against Mohs 5.5–6 for Augite.
Which is more valuable, Aegirine or Augite?
Typical specimens of Aegirine and Augite trade in a similar range, around $20.
