Comparison · Feldspar Group vs Tektites
Feldspar vs Moldavite
Feldspar and Moldavite are easy to confuse. 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 Feldspar and Moldavite
- Both sit near Mohs 6–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Hold a thin edge to the light: Feldspar is Transparent to translucent, Moldavite is translucent.
- They overlap in green, but Feldspar also comes in pink, gray, and clear.
- Well-formed crystals give it away: Feldspar is Monoclinic to Triclinic (depending on species), Moldavite is amorphous.
Feldspar vs Moldavite properties
| Property | Feldspar | Moldavite |
|---|---|---|
| Type | Feldspar Group | Tektites |
| Mohs hardness | 6–6.5 | 5.5 |
| Luster | Vitreous to pearly | vitreous |
| Streak | White | White |
| Transparency | Transparent to translucent | translucent |
| Specific gravity | 2.55–2.76 | 2.4 |
| Crystal system | Monoclinic to Triclinic (depending on species) | amorphous |
| Common colors | White, Pink, Gray, Green (amazonite), Colorless | Forest Green, Olive Green |
| Rarity | common | rare |
| Typical specimen value | $2–$150+ | $50–$2000+ |
Which is more valuable?
Moldavite is usually the more valuable of the two: a typical collector specimen runs about $200 against $20 for Feldspar, and premium Moldavite can reach $2000 or more.
About Feldspar
Feldspar is not a single mineral but a group of related aluminosilicate minerals, comprising the potassium feldspars, orthoclase, microcline, and sanidine, and the plagioclase series running from albite to anorthite, together making up roughly 60 percent of Earth's crust by volume. All share a similar framework silicate structure, two cleavage directions near 90 degrees, and moderate hardness, but differ in composition, color, and crystal system. As the most abundant mineral group on the planet, feldspar defines granite, basalt, gneiss, and countless other rock types.
About Moldavite
Moldavite is a green tektite formed by a meteorite impact about 15 million years ago. Found only in the Czech Republic, it's prized by collectors and crystal enthusiasts.
Feldspar vs Moldavite FAQ
Is Feldspar the same as Moldavite?
No. Feldspar is a feldspar group while Moldavite is a tektite. 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 Feldspar from Moldavite?
Both sit near Mohs 6–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hold a thin edge to the light: Feldspar is Transparent to translucent, Moldavite is translucent. They overlap in green, but Feldspar also comes in pink, gray, and clear.
Which is harder, Feldspar or Moldavite?
Feldspar is harder: Mohs 6–6.5 against Mohs 5.5 for Moldavite.
Which is more valuable, Feldspar or Moldavite?
Moldavite is usually the more valuable of the two: a typical collector specimen runs about $200 against $20 for Feldspar, and premium Moldavite can reach $2000 or more.
