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 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hoganite leaves a pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Hoganite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, green-blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, efflorescent crusts.
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. 2); streak differs — Hoganite leaves pale blue, Malachite leaves light green.
How to tell apart: Azurite is the harder of the two (Mohs 3.5-4 vs. 2); streak differs — Hoganite leaves pale blue, Azurite leaves light blue; luster reads vitreous on Hoganite and vitreous to dull on Azurite.
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
- 2
- Density
- 2.1 g/cm³
- Colors
- Streak
- Pale Blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Efflorescent Crusts
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper-rich Sulfide Deposits
- Typical price
- $50-500 depending on specimen quality and rarity
Where rockhounds find hoganite
Classic worldwide localities
- Broken Hill, New South Wales, Australia
Field-hunting tip
Look in oxidized zones of copper-rich sulfide deposits country — that is the host setting where hoganite typically forms. If you start seeing azurite, malachite, sampleite in float, you are in the right ground. Field specimens usually show a tabular crystals, efflorescent crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find hoganite on the map
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