Clinojimthompsonite is a rare chain silicate mineral that forms as a structural variation of jimthompsonite. It is typically found in association with other magnesium silicates in altered ultramafic rocks and is often difficult to distinguish from its orthorhombic counterpart without X-ray diffraction analysis.
Is this clinojimthompsonite?
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 clinojimthompsonite with a known reference. Clinojimthompsonite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Clinojimthompsonite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Clinojimthompsonite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: green, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Clinojimthompsonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Jimthompsonite is the harder of the two (Mohs 5-6 vs. 2-3).
How to tell apart: Anthophyllite is the harder of the two (Mohs 5.5-6 vs. 2-3).
How to tell apart: Clinojimthompsonite is noticeably harder (Mohs 2-3 vs. 1); luster reads vitreous on Clinojimthompsonite and pearly on Talc.
Often found alongside clinojimthompsonite
Minerals reported to co-occur with clinojimthompsonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mg,Fe)₅Si₆O₁₆(OH)₂
- Mohs hardness
- 2-3
- Density
- 3.3 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphic Ultramafic Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find clinojimthompsonite
Classic worldwide localities
- Vermont, USA
- Pennsylvania, USA
Field-hunting tip
Look in metamorphic ultramafic rocks country, the host setting where clinojimthompsonite typically forms. If you start seeing jimthompsonite, anthophyllite, talc in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find clinojimthompsonite on the map
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