Hatrurite is an extremely rare calcium silicate mineral primarily known from combustion metamorphic complexes. It forms as a product of high-temperature reactions in carbonate-rich rocks and is chemically analogous to alite found in Portland cement clinker.
Is this hatrurite?
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 hatrurite with a known reference. Hatrurite 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. Hatrurite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hatrurite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: equant crystals, granular.
Often confused with
Hatrurite vs. its common look-alikes — and how to tell them apart in the field.


How to tell apart: Larnite is the harder of the two (Mohs 6 vs. 3).

How to tell apart: Brownmillerite is the harder of the two (Mohs 5-6 vs. 3); streak differs — Hatrurite leaves white, Brownmillerite leaves brown; luster reads vitreous on Hatrurite and submetallic on Brownmillerite.
Often found alongside hatrurite
Minerals reported to co-occur with hatrurite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃SiO₅
- Mohs hardness
- 3
- Density
- 3.18 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Equant Crystals, Granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Pyrometamorphic Rocks of The Hatrurim Formation
- Typical price
- $50-300 per specimen
Where rockhounds find hatrurite
Classic worldwide localities
- Hatrurim Formation, Israel
- Jebel Harmun, Palestinian Authority
- Maqarin, Jordan
Field-hunting tip
Look in pyrometamorphic rocks of the hatrurim formation country — that is the host setting where hatrurite typically forms. If you start seeing larnite, brownmillerite, portlandite in float, you are in the right ground. Field specimens usually show a equant crystals, granular habit, so train your eye for that shape before scanning the outcrop.


