Coloradoite is a rare mercury telluride mineral often found in association with gold and silver deposits. It typically appears as massive, dark grey metallic grains that lack visible cleavage, and it is most famous for its occurrences in tellurium-rich epithermal vein systems.
Is this coloradoite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch coloradoite with a known reference. Coloradoite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: bright metallic.
- 4Match the color rangeCompare against the expected color range: grayish black, black.
- 5Look at form & habitCrystal system: cubic. Typical habit: granular, massive.
Often confused with
Coloradoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Coloradoite leaves black, Galena leaves lead-gray; luster reads bright metallic on Coloradoite and metallic on Galena.
How to tell apart: Luster reads bright metallic on Coloradoite and metallic, commonly splendent on Tetrahedrite.
How to tell apart: Luster reads bright metallic on Coloradoite and metallic on Altaite.
Often found alongside coloradoite
Minerals reported to co-occur with coloradoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- HgTe
- Mohs hardness
- 2.5
- Density
- 8.10 g/cm³
- Colors
- Streak
- Black
- Luster
- Bright metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Granular, massive
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Research
- Host rock
- In hydrothermal tellurium-bearing precious metal veins
Where rockhounds find coloradoite
Classic worldwide localities
- Good Hope mine, Vulcan, Gunnison Co., Colorado, USA
- La Plata district, La Plata Co., Colorado, USA
- Keystone, Mountain Lion, Smuggler, and Ellen mines, Boulder Co. (type locality), Colorado, USA
- Cresson mine, Cripple Creek district, Teller Co., Colorado, USA
- A number of mines in the Kirkland Lake district, in the Hemlo gold deposit, Thunder Bay district, and at Hollinger in the Porcupine district, Ontario, Canada
- Found at the Ardeen mine and the Robb-Montbray mine, Quebec, Canada
Field-hunting tip
Where it forms: In hydrothermal tellurium-bearing precious metal veins. If you start seeing altaite, calaverite, krennerite in float, you are in the right ground. Typical habit: granular, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify coloradoite?+
Where is coloradoite found?+
Is coloradoite safe to handle?+
What rocks look like coloradoite?+
What minerals are found with coloradoite?+
What kind of rock does coloradoite form in?+
What is coloradoite used for?+
Find coloradoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
