Tondiite is a rare copper magnesium chloride hydroxide mineral found in the oxidation zones of copper-bearing deposits. It typically forms as small, dark green platy crystals or granular masses that can easily be mistaken for other members of the atacamite group.
Is this tondiite?
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 tondiite with a known reference. Tondiite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tondiite leaves a light green streak.
- 3Read the lusterHold the specimen under a strong light. Tondiite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark green, blackish green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, granular aggregates.
Often confused with
Tondiite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Tondiite leaves light green, Atacamite leaves apple green; luster reads vitreous on Tondiite and adamantine to vitreous on Atacamite.
How to tell apart: Streak differs, so Tondiite leaves light green, Paratacamite leaves apple green; luster reads vitreous on Tondiite and adamantine on Paratacamite.
How to tell apart: Streak differs, so Tondiite leaves light green, Clinoatacamite leaves apple green.
Often found alongside tondiite
Minerals reported to co-occur with tondiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃Mg(OH)₆Cl₂
- Mohs hardness
- 3
- Density
- 4.12 g/cm³
- Colors
- Streak
- Light Green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals, Granular Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Hydrothermal Copper Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find tondiite
Classic worldwide localities
- Tondi, Oravitsa, Romania
- Chile
- Arizona, USA
Field-hunting tip
Look in oxidized hydrothermal copper deposits country, the host setting where tondiite typically forms. If you start seeing quartz, goethite, chrysocolla in float, you are in the right ground. Field specimens usually show a platy crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find tondiite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
