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 — that is 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.
