Blue sapphire is the highly prized, iron and titanium-bearing gem variety of corundum. Collectors look for strong, vibrant blue saturation and often seek crystals with characteristic hexagonal growth lines or rutile silk inclusions.
Is this blue sapphire?
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 blue sapphire with a known reference. Blue Sapphire sits at Mohs 9, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Blue Sapphire leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Blue Sapphire typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, violet-blue, greenish-blue.
- 5Look at form & habitCrystal system: trigonal. Typical habit: hexagonal bipyramidal crystals, barrel-shaped.
Often confused with
Blue Sapphire vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Blue Sapphire is noticeably harder (Mohs 9 vs. 6.5-7).
How to tell apart: Blue Sapphire is noticeably harder (Mohs 9 vs. 6-6.5).
How to tell apart: Blue Sapphire is noticeably harder (Mohs 9 vs. 7-7.5).
Often found alongside blue sapphire
Minerals reported to co-occur with blue sapphire. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₂O₃
- Mohs hardness
- 9
- Density
- 3.98-4.06 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Hexagonal Bipyramidal Crystals, Barrel-shaped
- Cleavage
- None
- Rarity
- Common
- Uses
- Gemstone, Jewelry, Collector
- Host rock
- Pegmatites, Basalt-related Alluvial Deposits, Metamorphic Marbles
- Typical price
- $50-5000+ per carat depending on quality and origin
Where rockhounds find blue sapphire
1 mapped spotsClassic worldwide localities
- Sri Lanka
- Myanmar
- Madagascar
- Kashmir
- Thailand
Field-hunting tip
Look in pegmatites, basalt-related alluvial deposits, metamorphic marbles country, the host setting where blue sapphire typically forms. If you start seeing spinel, garnet, zircon in float, you are in the right ground. Field specimens usually show a hexagonal bipyramidal crystals, barrel-shaped habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in North Carolina. Start trip planning there.
Common questions
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Find blue sapphire on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
