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, 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
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
