Serendibite is an exceptionally rare borosilicate mineral prized by collectors for its deep blue to green-blue color. It typically forms in contact metamorphic zones where boron-rich fluids interact with carbonate rocks. Due to its scarcity and refractive indices, it is one of the most expensive and sought-after gems in the mineral world.
Is this serendibite?
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 serendibite with a known reference. Serendibite 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. Serendibite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Serendibite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-green, black, gray.
- 5Look at form & habitCrystal system: triclinic. Typical habit: anhedral to subhedral grains or tabular crystals.
Often confused with
Serendibite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside serendibite
Minerals reported to co-occur with serendibite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Mg₃Al₄Si₃B₄O₂₀
- Mohs hardness
- 6.5-7
- Density
- 3.4-3.5 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Anhedral to Subhedral Grains or Tabular Crystals
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector, Gemstone
- Host rock
- Metamorphosed Limestone or Dolomitic Skarns
- Typical price
- $500-5000+ per carat for facet-grade material
Where rockhounds find serendibite
Classic worldwide localities
- Sri Lanka
- Myanmar
- USA
- Canada
- Tanzania
Field-hunting tip
Look in metamorphosed limestone or dolomitic skarns country, the host setting where serendibite typically forms. If you start seeing diopside, spinel, phlogopite in float, you are in the right ground. Field specimens usually show a anhedral to subhedral grains or tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify serendibite?+
Where is serendibite found?+
How much is serendibite worth?+
What rocks look like serendibite?+
What minerals are found with serendibite?+
What kind of rock does serendibite form in?+
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Find serendibite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
