Sinhalite is a rare magnesium aluminum borate mineral that was historically mistaken for olivine or chrysoberyl due to its similar appearance. It typically occurs as transparent, brownish-yellow crystals and is primarily sought after by gem collectors for its high refractive index and distinct physical properties.
Is this sinhalite?
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 sinhalite with a known reference. Sinhalite sits at Mohs 6.5-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sinhalite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Sinhalite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, greenish-brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals, rounded grains.
Often confused with
Sinhalite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside sinhalite
Minerals reported to co-occur with sinhalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgAlBO₄
- Mohs hardness
- 6.5-7
- Density
- 3.47-3.51 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals, Rounded Grains
- Cleavage
- Distinct in One Direction
- Rarity
- Rare
- Uses
- Gemstone, Collector
- Host rock
- Metamorphosed Dolomite Marbles, Skarns
- Typical price
- $20-200 per carat for cut gems
Where rockhounds find sinhalite
Classic worldwide localities
- Ratnapura, Sri Lanka
- Tanzania
- Myanmar
- Madagascar
Field-hunting tip
Look in metamorphosed dolomite marbles, skarns country — that is the host setting where sinhalite typically forms. If you start seeing spinel, sapphire, zircon in float, you are in the right ground. Field specimens usually show a prismatic crystals, rounded grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find sinhalite on the map
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