Yaroslavite is a very rare calcium aluminum fluoride hydroxide mineral. It typically occurs as small tabular crystals or massive grains within hydrothermal vein deposits and is highly prized by advanced mineral collectors for its scarcity.
Is this yaroslavite?
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 yaroslavite with a known reference. Yaroslavite sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: fibrous, radial, spherical.
Often confused with
Yaroslavite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside yaroslavite
Minerals reported to co-occur with yaroslavite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃Al₂F₁₀(OH)₂·H₂O
- Mohs hardness
- 4.5
- Density
- 3.09 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Fibrous, radial, spherical
- Cleavage
- One direction, pinacoidal
- Fluorescence
- Pale violet under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From the oxidized zone of a banded sellaite-tourmaline-fluorite deposit
Where rockhounds find yaroslavite
Classic worldwide localities
- Yaroslavsk tin deposit, 50 km south of Lake Khanka, Primorskiy Territory, Siberia, Russia
Field-hunting tip
Where it forms: From the oxidized zone of a banded sellaite-tourmaline-fluorite deposit. If you start seeing sellaite, gearksutite, chukhrovite- in float, you are in the right ground. Typical habit: fibrous, radial, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yaroslavite?+
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What rocks look like yaroslavite?+
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Find yaroslavite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
