Heterogenite is a cobalt oxyhydroxide often found in the weathered zones of cobalt-rich deposits. It is most recognized by its characteristic botryoidal or kidney-like habit and its deep black, submetallic luster, frequently coating other secondary copper and cobalt minerals.
Is this heterogenite?
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 heterogenite with a known reference. Heterogenite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Heterogenite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Heterogenite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: black, brownish-black, reddish-brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: botryoidal, reniform, massive, earthy.
Often confused with
Heterogenite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Romanèchite is the harder of the two (Mohs 5-6 vs. 3-4); streak differs — Heterogenite leaves black, Romanèchite leaves shiny brownish black; luster reads submetallic on Heterogenite and submetallic to dull on Romanèchite.
How to tell apart: Iron Ore is the harder of the two (Mohs 5-6.5 vs. 3-4); streak differs — Heterogenite leaves black, Iron Ore leaves reddish-brown to black; luster reads submetallic on Heterogenite and metallic to submetallic on Iron Ore.
How to tell apart: Streak differs — Heterogenite leaves black, Limonite leaves yellowish-brown; luster reads submetallic on Heterogenite and submetallic to earthy on Limonite.
Often found alongside heterogenite
Minerals reported to co-occur with heterogenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CoO(OH)
- Mohs hardness
- 3-4
- Density
- 4.4-4.8 g/cm³
- Streak
- Black
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Botryoidal, Reniform, Massive, Earthy
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Cobalt Ore
- Host rock
- Oxidized Zones of Cobalt-bearing Ore Deposits
- Typical price
- $10-100 per specimen
Where rockhounds find heterogenite
Classic worldwide localities
- Katanga Province, Democratic Republic of the Congo
- Bou Azzer, Morocco
- Schneeberg, Germany
- Goodsprings, Nevada, USA
Field-hunting tip
Look in oxidized zones of cobalt-bearing ore deposits country — that is the host setting where heterogenite typically forms. If you start seeing cobaltite, skutterudite, malachite in float, you are in the right ground. Field specimens usually show a botryoidal, reniform, massive, earthy habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify heterogenite?+
Where is heterogenite found?+
How much is heterogenite worth?+
Is heterogenite safe to handle?+
What rocks look like heterogenite?+
What minerals are found with heterogenite?+
What kind of rock does heterogenite form in?+
What is heterogenite used for?+
Find heterogenite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
