Kilchoanite is a rare calcium silicate mineral typically found in high-temperature contact metamorphic zones. It usually occurs as fine-grained masses or lamellar intergrowths associated with other skarn minerals like rankinite and larnite. It is primarily a collector's mineral of interest for those specializing in rare silicate species from specific localities like Ardnamurchan.
Is this kilchoanite?
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 kilchoanite with a known reference. Kilchoanite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Kilchoanite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kilchoanite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: lamellar, massive, granular.
Often confused with
Kilchoanite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kilchoanite
Minerals reported to co-occur with kilchoanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃Si₂O₇
- Mohs hardness
- 5
- Density
- 2.98 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Lamellar, Massive, Granular
- Cleavage
- Distinct On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Limestone or Skarn Deposits
- Typical price
- $20-100 per specimen
Where rockhounds find kilchoanite
Classic worldwide localities
- Kilchoan, Ardnamurchan, Scotland
- Christmas Mountains, Arizona, USA
- Bellerberg, Germany
Field-hunting tip
Look in metamorphosed limestone or skarn deposits country, the host setting where kilchoanite typically forms. If you start seeing rankinite, larnite, calcite in float, you are in the right ground. Field specimens usually show a lamellar, massive, granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find kilchoanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
