Comparison · Minerals vs Silicate Minerals
Diopside vs Lazurite
Diopside and Lazurite are easy to confuse. Both sit near Mohs 5.5–6.5, 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 Diopside and Lazurite
- Both sit near Mohs 5.5–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Diopside leaves a white streak on unglazed porcelain, Lazurite leaves light blue.
- Diopside feels noticeably heavier for its size (specific gravity 3.2–3.3 versus 2.4 for Lazurite).
- Hold a thin edge to the light: Diopside is Transparent to translucent, Lazurite is translucent.
- They overlap in blue and purple, but Diopside also comes in green, white, gray, black, and multicolored.
- Well-formed crystals give it away: Diopside is Monoclinic, Lazurite is cubic.
Diopside vs Lazurite properties
| Property | Diopside | Lazurite |
|---|---|---|
| Type | Minerals | Silicate Minerals |
| Mohs hardness | 5.5–6.5 | 5.25 |
| Luster | Vitreous | vitreous |
| Streak | White | Light blue |
| Transparency | Transparent to translucent | translucent |
| Specific gravity | 3.2–3.3 | 2.4 |
| Crystal system | Monoclinic | cubic |
| Common colors | Light to dark green, White, Gray, Blue-violet (violane), Black (chromian varieties) | Blue, Deep blue, Azure blue, Violet blue |
| Rarity | common | rare |
| Typical specimen value | $2–$150+ | $10–$600+ |
Which is more valuable?
Lazurite is usually the more valuable of the two: a typical collector specimen runs about $80 against $20 for Diopside, and premium Lazurite can reach $600 or more.
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.
About Lazurite
Lazurite is a deep blue feldspathoid mineral of the sodalite group and the main coloring component of the rock lapis lazuli. It occurs as rounded grains and rare dodecahedral crystals in metamorphosed limestone.
Diopside vs Lazurite FAQ
Is Diopside the same as Lazurite?
No. Diopside is a mineral while Lazurite is a silicate mineral. Both sit near Mohs 5.5–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Diopside from Lazurite?
Both sit near Mohs 5.5–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Diopside leaves a white streak on unglazed porcelain, Lazurite leaves light blue. Diopside feels noticeably heavier for its size (specific gravity 3.2–3.3 versus 2.4 for Lazurite).
Which is harder, Diopside or Lazurite?
Diopside is harder: Mohs 5.5–6.5 against Mohs 5.25 for Lazurite.
Which is more valuable, Diopside or Lazurite?
Lazurite is usually the more valuable of the two: a typical collector specimen runs about $80 against $20 for Diopside, and premium Lazurite can reach $600 or more.
