Comparison · Minerals vs Sulfide Minerals
Fluorite vs Sphalerite
Fluorite and Sphalerite are easy to confuse. Both sit near Mohs 4, 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 Fluorite and Sphalerite
- Both sit near Mohs 4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Fluorite leaves a white streak on unglazed porcelain, Sphalerite leaves brownish white to pale yellow.
- Luster is different: Fluorite is vitreous while Sphalerite is resinous.
- Sphalerite feels noticeably heavier for its size (specific gravity 4.05 versus 3.2 for Fluorite).
- They overlap in green and yellow, but Fluorite also comes in purple, blue, clear, and pink and Sphalerite also comes in brown, black, and red.
Fluorite vs Sphalerite properties
| Property | Fluorite | Sphalerite |
|---|---|---|
| Type | Minerals | Sulfide Minerals |
| Mohs hardness | 4 | 3.75 |
| Luster | vitreous | resinous |
| Streak | White | Brownish white to pale yellow |
| Transparency | transparent | transparent |
| Specific gravity | 3.2 | 4.05 |
| Crystal system | cubic | cubic |
| Common colors | Purple, Green, Blue, Yellow, Colorless, Pink | Brown, Black, Yellow, Red, Green |
| Rarity | common | common |
| Typical specimen value | $5–$200+ | $5–$600+ |
Which is more valuable?
Sphalerite is usually the more valuable of the two: a typical collector specimen runs about $70 against $25 for Fluorite, and premium Sphalerite can reach $600 or more.
About Fluorite
Fluorite is a colorful mineral that often exhibits multiple colors in a single specimen. It's the defining mineral for 4 on the Mohs hardness scale.
About Sphalerite
Sphalerite is zinc sulfide, the most important ore of zinc. It ranges from honey-yellow and green to brown and black, with a distinctive resinous to adamantine luster and perfect dodecahedral cleavage in six directions.
Fluorite vs Sphalerite FAQ
Is Fluorite the same as Sphalerite?
No. Fluorite is a mineral while Sphalerite is a sulfide mineral. Both sit near Mohs 4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Fluorite from Sphalerite?
Both sit near Mohs 4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Fluorite leaves a white streak on unglazed porcelain, Sphalerite leaves brownish white to pale yellow. Luster is different: Fluorite is vitreous while Sphalerite is resinous.
Which is harder, Fluorite or Sphalerite?
They are about equally hard, both near Mohs 4.
Which is more valuable, Fluorite or Sphalerite?
Sphalerite is usually the more valuable of the two: a typical collector specimen runs about $70 against $25 for Fluorite, and premium Sphalerite can reach $600 or more.
