Jaffeite is a rare calcium silicate hydroxide found in high-temperature metamorphic environments such as the Hatrurim formation. It typically forms colorless to white prismatic crystals or radial aggregates and is prized by micromount collectors for its distinct, albeit rare, crystalline structure.
Is this jaffeite?
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 jaffeite with a known reference. Jaffeite sits at Mohs 3.5, 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: colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: prismatic crystals, radial aggregates.
Often confused with
Jaffeite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside jaffeite
Minerals reported to co-occur with jaffeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₆Si₂O₇(OH)₆
- Mohs hardness
- 3.5
- Density
- 2.65 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Prismatic crystals, radial aggregates
- Cleavage
- {1010}, imperfect, suspected
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Closely associated with or enclosed by defernite within low-grade metamorphic rocks
Where rockhounds find jaffeite
Classic worldwide localities
- Kombat mine, 49 km south of Tsumeb, Namibia
Field-hunting tip
Where it forms: Closely associated with or enclosed by defernite within low-grade metamorphic rocks. If you start seeing defernite, hausmannite, apatite in float, you are in the right ground. Typical habit: prismatic crystals, radial aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jaffeite?+
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Find jaffeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
