Comparison · Sulfide Minerals
Molybdenite vs Stibnite
Molybdenite and Stibnite are easy to confuse because both are sulfide minerals. Both sit near Mohs 1.25, 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 Molybdenite and Stibnite
- Both sit near Mohs 1.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Molybdenite leaves a bluish gray streak on unglazed porcelain, Stibnite leaves lead gray.
- Both look metallic, so compare color, tarnish and weight rather than shine.
- Well-formed crystals give it away: Molybdenite is hexagonal, Stibnite is orthorhombic.
Molybdenite vs Stibnite properties
| Property | Molybdenite | Stibnite |
|---|---|---|
| Type | Sulfide Minerals | Sulfide Minerals |
| Mohs hardness | 1.25 | 2 |
| Luster | metallic | metallic |
| Streak | Bluish gray | Lead gray |
| Transparency | opaque | opaque |
| Specific gravity | 4.7 | 4.6 |
| Crystal system | hexagonal | orthorhombic |
| Common colors | Lead gray, Bluish gray | Lead gray, Steel gray, Silvery gray |
| Rarity | uncommon | uncommon |
| Typical specimen value | $8–$250+ | $10–$1500+ |
Which is more valuable?
Stibnite is usually the more valuable of the two: a typical collector specimen runs about $120 against $45 for Molybdenite, and premium Stibnite can reach $1500 or more.
About Molybdenite
Molybdenite is a soft, metallic molybdenum sulfide and the most important ore of molybdenum. It appears as bluish lead-gray flakes, plates, and foliated masses that feel greasy and leave a mark like graphite.
About Stibnite
Stibnite is antimony sulfide, the chief ore of antimony. It is famous for brilliant steel-gray metallic crystals that form long, slender, often curved or radiating prismatic blades with perfect lengthwise cleavage.
Molybdenite vs Stibnite FAQ
Is Molybdenite the same as Stibnite?
No. Both are sulfide minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 1.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Molybdenite from Stibnite?
Both sit near Mohs 1.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Molybdenite leaves a bluish gray streak on unglazed porcelain, Stibnite leaves lead gray. Both look metallic, so compare color, tarnish and weight rather than shine.
Which is harder, Molybdenite or Stibnite?
Stibnite is harder: Mohs 2 against Mohs 1.25 for Molybdenite.
Which is more valuable, Molybdenite or Stibnite?
Stibnite is usually the more valuable of the two: a typical collector specimen runs about $120 against $45 for Molybdenite, and premium Stibnite can reach $1500 or more.
