Comparison · Minerals
Astrophyllite vs Bornite
Astrophyllite and Bornite are easy to confuse because both are minerals. Both sit near Mohs 3–3.5, 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 Astrophyllite and Bornite
- Both sit near Mohs 3–3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Astrophyllite leaves a brownish yellow streak on unglazed porcelain, Bornite leaves grayish black.
- Both look metallic, so compare color, tarnish and weight rather than shine.
- Bornite feels noticeably heavier for its size (specific gravity 4.9–5.3 versus 3.3–3.4 for Astrophyllite).
- Hold a thin edge to the light: Astrophyllite is Translucent, Bornite is Opaque.
- They overlap in brown, red, and orange, but Astrophyllite also comes in yellow and Bornite also comes in blue, purple, and multicolored.
- Well-formed crystals give it away: Astrophyllite is Triclinic, Bornite is Orthorhombic (pseudocubic).
Astrophyllite vs Bornite properties
| Property | Astrophyllite | Bornite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 3–3.5 | 3–3.25 |
| Luster | Vitreous to pearly/submetallic sheen | Metallic |
| Streak | Brownish yellow | Grayish black |
| Transparency | Translucent | Opaque |
| Specific gravity | 3.3–3.4 | 4.9–5.3 |
| Crystal system | Triclinic | Orthorhombic (pseudocubic) |
| Common colors | Golden-yellow, Bronze, Copper-red, Brown | Copper red to brownish bronze (fresh), Iridescent purple-blue tarnish (peacock ore) |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Astrophyllite and Bornite trade in a similar range, around $20.
About Astrophyllite
Astrophyllite is a rare, structurally complex silicate of potassium, sodium, iron, titanium, and manganese that forms bronze to golden-brown bladed or feathery crystal sprays. Its name, from the Greek for star leaf, describes the radiating star-like clusters it builds within alkaline igneous rocks. The mineral is prized more for its striking metallic sheen and habit than for gem use, since it never occurs transparent.
About Bornite
Bornite is a copper iron sulfide mineral with the formula Cu5FeS4, prized by mineral collectors for the flashy iridescent tarnish that earns it the nickname peacock ore. Freshly broken surfaces show a coppery, brownish-bronze metallic color that oxidizes within hours to purple, blue, and pink iridescence. It is an important, though secondary, copper ore mineral found in many sulfide deposits worldwide.
Astrophyllite vs Bornite FAQ
Is Astrophyllite the same as Bornite?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 3–3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Astrophyllite from Bornite?
Both sit near Mohs 3–3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Astrophyllite leaves a brownish yellow streak on unglazed porcelain, Bornite leaves grayish black. Both look metallic, so compare color, tarnish and weight rather than shine.
Which is harder, Astrophyllite or Bornite?
They are about equally hard, both near Mohs 3–3.5.
Which is more valuable, Astrophyllite or Bornite?
Typical specimens of Astrophyllite and Bornite trade in a similar range, around $20.
