Scawtite is a rare calcium silicate carbonate mineral typically found in metamorphosed limestone deposits. Collectors look for its characteristic platy habit or massive formations in hydrothermal contact zones. It is most famous for its discovery at the Scawt Hill locality in Northern Ireland.
Is this scawtite?
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 scawtite with a known reference. Scawtite sits at Mohs 4.5-5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Scawtite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Scawtite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, light gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, granular, massive.
Often confused with
Scawtite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside scawtite
Minerals reported to co-occur with scawtite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₇Si₆O₁₈(CO₃)·2H₂O
- Mohs hardness
- 4.5-5
- Density
- 2.75 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Granular, Massive
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Metamorphosed Limestone (skarn Zones)
- Typical price
- $20-150 per specimen
Where rockhounds find scawtite
Classic worldwide localities
- Scawt Hill, Northern Ireland
- Kilchoan, Scotland
- Franklin, New Jersey, USA
- Fuka, Japan
Field-hunting tip
Look in metamorphosed limestone (skarn zones) country — that is the host setting where scawtite typically forms. If you start seeing calcite, larnite, portlandite in float, you are in the right ground. Field specimens usually show a platy crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find scawtite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
