Tokkoite is a rare potassium-calcium silicate mineral found primarily in the alkaline rocks of the Murun Massif in Siberia. It typically appears as yellowish-brown fibrous or radiating aggregates and is often associated with the mineral tinaksite. Due to its limited distribution, it is highly sought after by systematic mineral collectors.
Is this tokkoite?
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 tokkoite with a known reference. Tokkoite 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: brownish yellow, colorless, light yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: aggregates, columnar, radial.
Often confused with
Tokkoite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside tokkoite
Minerals reported to co-occur with tokkoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Ca₄Si₇O₁₇(OH,F)₂
- Mohs hardness
- 4-5
- Density
- 2.761 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Aggregates, columnar, radial
- Cleavage
- Perfect on {010}, less perfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In nearly monomineralic segregations in an alkalic massif
Where rockhounds find tokkoite
Classic worldwide localities
- Magistral'nyi area, right bank of the Davan Stream, between the Chara and Tokko Rivers, in the Murun massif, southwest of Olekminsk, Yakutia, Russia
Field-hunting tip
Where it forms: In nearly monomineralic segregations in an alkalic massif. If you start seeing charoite, tinaksite, miserite in float, you are in the right ground. Typical habit: aggregates, columnar, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tokkoite?+
Where is tokkoite found?+
What rocks look like tokkoite?+
What minerals are found with tokkoite?+
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What is tokkoite used for?+
Find tokkoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
