Hoganite is a rare copper acetate mineral typically found as a result of the alteration of organic matter by copper-bearing solutions. It usually appears as vibrant blue, tabular crystals often associated with other secondary copper minerals in the oxidized zones of ore deposits.
Is this hoganite?
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 hoganite with a known reference. Hoganite sits at Mohs 1.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: bluish green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, tabular, water soluble.
Often confused with
Hoganite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Malachite is the harder of the two (Mohs 3.5-4 vs. 1.5); luster reads vitreous on Hoganite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
How to tell apart: Azurite is the harder of the two (Mohs 3.5-4 vs. 1.5).
Often found alongside hoganite
Minerals reported to co-occur with hoganite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu(CH₃COO)₂·H₂O
- Mohs hardness
- 1.5
- Density
- 1.910 g/cm³
- Colors
- Streak
- Pale blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, tabular, water soluble
- Cleavage
- On {001}, perfect; on {110}, distinct (synthetic)
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed in ferruginous gossan by reaction of oxidized zone metallic minerals with decaying vegetable matter provided by leaf litter and possibly mine timbers
Where rockhounds find hoganite
Classic worldwide localities
- Potosi Ag–Pb–Zn pit, two km northeast of Broken Hill, New South Wales, Australia
Field-hunting tip
Where it forms: Formed in ferruginous gossan by reaction of oxidized zone metallic minerals with decaying vegetable matter provided by leaf litter and possibly mine timbers. If you start seeing paceite, linarite, malachite in float, you are in the right ground. Typical habit: prismatic, tabular, water soluble. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hoganite?+
Where is hoganite found?+
Is hoganite safe to handle?+
What rocks look like hoganite?+
What minerals are found with hoganite?+
What kind of rock does hoganite form in?+
What is hoganite used for?+
Find hoganite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
