Yanomamite is an extremely rare indium arsenate mineral found in specific hydrothermal environments. Collectors generally look for its distinctive yellow to yellow-green micro-crystalline crusts which appear in association with arsenopyrite deposits.
Is this yanomamite?
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 yanomamite with a known reference. Yanomamite 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. Yanomamite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Yanomamite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: microcrystalline crusts, tiny tabular crystals.
Often confused with
Yanomamite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Scorodite is the harder of the two (Mohs 3.5-4 vs. 2); streak differs, so Yanomamite leaves yellow, Scorodite leaves white; luster reads vitreous on Yanomamite and vitreous to sub-adamantine on Scorodite.
How to tell apart: Mansfieldite is the harder of the two (Mohs 3.5-4 vs. 2); streak differs, so Yanomamite leaves yellow, Mansfieldite leaves white.
Often found alongside yanomamite
Minerals reported to co-occur with yanomamite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- InAsO₄·2H₂O
- Mohs hardness
- 2
- Density
- 3.32 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Microcrystalline Crusts, Tiny Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find yanomamite
Classic worldwide localities
- Yanomami mine, Brazil
- Tsumeb mine, Namibia
Field-hunting tip
Look in hydrothermal veins country, the host setting where yanomamite typically forms. If you start seeing arsenopyrite, cassiterite in float, you are in the right ground. Field specimens usually show a microcrystalline crusts, tiny tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yanomamite?+
Where is yanomamite found?+
How much is yanomamite worth?+
Is yanomamite safe to handle?+
What rocks look like yanomamite?+
What minerals are found with yanomamite?+
What kind of rock does yanomamite form in?+
What is yanomamite used for?+
Find yanomamite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
