Raw Stones
180 pieces
Tumbled Stones
162 pieces
Palm Stones
26 pieces
Crystal Points
23 pieces
Clusters & Geodes
112 pieces
Polished & Decor
155 pieces
Mineral Specimens
268 collector pieces
Crystal Chips
21 pieces
Browse everything
Every collection, one page.
View All Collections →
Aries
Mar 21 – Apr 19
Carnelian
›
Taurus
Apr 20 – May 20
Rose Quartz
›
Gemini
May 21 – Jun 20
Agate
›
Cancer
Jun 21 – Jul 22
Moonstone
›
Leo
Jul 23 – Aug 22
Citrine
›
Virgo
Aug 23 – Sep 22
Amazonite
›
Libra
Sep 23 – Oct 22
Blue Lace Agate
›
Scorpio
Oct 23 – Nov 21
Obsidian
›
Sagittarius
Nov 22 – Dec 21
Sodalite
›
Capricorn
Dec 22 – Jan 19
Black Tourmaline
›
Aquarius
Jan 20 – Feb 18
Amethyst
›
Pisces
Feb 19 – Mar 20
Aquamarine
›
Gifting?
A birthday stone is the safe bet.
Read the zodiac guide →
Bornite
Bornite is sulfide (copper iron), Cu₅FeS₄. In the hand, it rates 3 on the Mohs scale, and it runs bronze fresh and purple-blue iridescent tarnish. Metallic copper ore that tarnishes to muted purple-blue iridescence over a bronze base, heavier and softer than it looks. Copper deposits; notable: Mexico, Kazakhstan, Montana/Arizona (USA), Peru.
The geology.
Bornite carries the formula Cu₅FeS₄. It belongs to the orthorhombic (pseudo-cubic) system. Its listing category is sulfide (copper iron).
It sits at 3 on the Mohs scale. The surface reads metallic. Light behaviour is opaque. Specific gravity runs 5.0 to 5.1. The streak is gray-black. It breaks with uneven fracture; brittle.
Metallic copper ore that tarnishes to muted purple-blue iridescence over a bronze base, heavier and softer than it looks.
It turns up mostly as raw chunks or massive ore pieces.
The origins.
Copper deposits; notable: Mexico, Kazakhstan, Montana/Arizona (USA), Peru.
On value, the database notes: common and affordable.
Traditional associations.
In energy work traditions, associated with joy and fresh perspective.
This is lore, and we label it as lore. The measurable facts are further up the page.
Spotting the real thing.
Metallic copper ore that tarnishes to muted purple-blue iridescence over a bronze base, heavier and softer than it looks.
Most retail 'peacock ore' is chalcopyrite flash-treated with acid for rainbow tarnish, pretty, but mislabeled bornite.
| Looks like | How to tell them apart |
|---|---|
| Treated chalcopyrite | Most vivid 'peacock ore' sold is acid-treated chalcopyrite, its rainbow is loud magenta-teal; bornite tarnish is subtler purple-bronze |
| Titanium-coated stone | Coated pieces are uniformly metallic rainbow with no bronze undertone |
| Pyrite | Pyrite is pale brass, harder, and doesn't tarnish purple |
At-home tests.
A loupe and a window seat settle most questions about bornite. No workshop required.
| Test | What you should see |
|---|---|
| Scratch check | Knife scratches it easily (Mohs 3) |
| Scratch check | Fresh scratch shows bronze under the purple |
| By eye | Noticeably heavy (SG ~5) |
Anything that scratches, burns or dissolves the piece is a lab job. Get it appraised rather than testing it apart.
Care & handling.
At 3 on the Mohs scale this is a soft material. Keep it as a display piece, store it apart from harder stones, and skip daily-wear settings.
It breaks with uneven fracture; brittle, which is worth knowing before you set it or drop it.
Warm water and a soft cloth clean almost everything. Ultrasonic tanks, steamers and household cleaners are where pieces get ruined.
Copper sulfide, wash hands after handling crumbly material.
A deeper look.
Extended detail on composition, sourcing, authentication and market value.
The physical record
The formula on record is Cu₅FeS₄. Crystal system: Orthorhombic (pseudo-cubic). Specific gravity: 5.0 to 5.1. Streak: Gray-black. Cleavage and fracture: Uneven fracture; brittle.
How it reaches the market
Copper deposits; notable: Mexico, Kazakhstan, Montana/Arizona (USA), Peru.
What it gets confused with
Treated chalcopyrite: Most vivid 'peacock ore' sold is acid-treated chalcopyrite, its rainbow is loud magenta-teal; bornite tarnish is subtler purple-bronze. Titanium-coated stone: Coated pieces are uniformly metallic rainbow with no bronze undertone. Pyrite: Pyrite is pale brass, harder, and doesn't tarnish purple.
What it is worth
Common and affordable.
Where buyers get caught
Most retail 'peacock ore' is chalcopyrite flash-treated with acid for rainbow tarnish, pretty, but mislabeled bornite.
One more thing
Miners call it peacock ore for the tarnish that blooms within hours of breaking a fresh surface.
An education-first guide.
No product links here. We do not sell bornite, and a guide that only covers our own shelves would not be much of a guide.
Explore the Crystal GuideThe Slow Note
New stones go to the list first.
No forwarding, no selling. Unsubscribe in one click. Privacy