Bokite is a rare borate mineral belonging to the vonsenite group, recognized by its dark, acicular, or fibrous crystal aggregates. It is primarily found in metasomatic skarn deposits where it forms in association with high-temperature contact metamorphism of limestones.
Is this bokite?
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 bokite with a known reference. Bokite 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. Streak: black, may be brownish black.
- 3Read the lusterHold the specimen under a strong light. Luster: semimetallic to dull.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: encrustations, radial, reniform.
Often confused with
Bokite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Vonsenite is the harder of the two (Mohs 5 vs. ~3); streak differs, so Bokite leaves black, may be brownish black, Vonsenite leaves brownish black; luster reads semimetallic to dull on Bokite and metallic to submetallic, silky if fibrous on Vonsenite.
How to tell apart: Ludwigite is the harder of the two (Mohs 5-5.5 vs. ~3); luster reads semimetallic to dull on Bokite and submetallic on Ludwigite.
Often found alongside bokite
Minerals reported to co-occur with bokite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Al,Fe)₁.₃(V,V,Fe)₈O₂₀·7.5H₂O
- Mohs hardness
- ~3
- Density
- 2.97-3.10 g/cm³
- Colors
- Streak
- Black, may be brownish black
- Luster
- Semimetallic to dull
- Transparency
- Opaque, translucent in thinnest fragments
- Crystal system
- Monoclinic
- Crystal habit
- Encrustations, radial, reniform
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In carbonaceous vanadiferous shales (Kurumsak area, Kazakhstan); in rich U–V ore in Triassic stream channels and impregnating sandstone (Monument No. 2 mine, Arizona, USA)
Where rockhounds find bokite
Classic worldwide localities
- Monument No. 2 mine, Apache Co., Arizona, USA
- Fish, Eureka Co., and near Cockalorum Wash, Nye Co., Nevada, USA
- Wilson Springs (Potash Sulphur Springs) mine, Garland Co., Arkansas, USA
- Balasauskandyk and nearby Kurumsak and Ran districts, northwestern Kara-Tau Mountains, and in the Dzhebagly Mountains, Talass Alatau Range, Kazakhstan
Field-hunting tip
Where it forms: In carbonaceous vanadiferous shales (Kurumsak area, Kazakhstan); in rich U–V ore in Triassic stream channels and impregnating sandstone (Monument No. 2 mine, Arizona, USA). If you start seeing jarosite, kazakhstanite, navajoite in float, you are in the right ground. Typical habit: encrustations, radial, reniform. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bokite?+
Where is bokite found?+
Is bokite safe to handle?+
What rocks look like bokite?+
What minerals are found with bokite?+
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Find bokite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
