Asisite is a rare lead-silicate mineral found almost exclusively in the oxidized zones of the famous Tsumeb Mine in Namibia. It typically forms bright yellow, thin tabular crystals that appear as delicate, transparent plates within mineralized cavities.
Is this asisite?
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 asisite with a known reference. Asisite 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: light yellow to white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: green yellow, yellow.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: platy.
Often confused with
Asisite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Asisite leaves light yellow to white, Penfieldite leaves white.
How to tell apart: Streak differs, so Asisite leaves light yellow to white, Laurionite leaves white.
How to tell apart: Asisite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so Asisite leaves light yellow to white, Mendipite leaves white; luster reads adamantine on Asisite and pearly to silky on cleavages; resinous to adamantine on fractures on Mendipite.
Often found alongside asisite
Minerals reported to co-occur with asisite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₇SiO₈Cl₂
- Mohs hardness
- 3.5
- Density
- 8.041 g/cm³
- Colors
- Streak
- Light yellow to white
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Platy
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In manganese silicate lenses nearby a sulfide ore body
Where rockhounds find asisite
Classic worldwide localities
- Kombat mine, 49 km south of Tsumeb, Namibia
Field-hunting tip
Where it forms: In manganese silicate lenses nearby a sulfide ore body. If you start seeing hematophanite, barite, jacobsite in float, you are in the right ground. Typical habit: platy. Train your eye for that shape before scanning the outcrop.
Common questions
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Find asisite on the map
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