Andradite is the calcium-iron member of the garnet group, famous for its distinct crystal forms and sometimes high luster. Collectors often seek out the brilliant green variety known as Demantoid or the glossy black variety called Melanite. It is most commonly found as a contact metamorphic mineral in skarns and limestone deposits.
Is this andradite?
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 andradite with a known reference. Andradite sits at Mohs 6.5-7.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Andradite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Andradite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, brown, green, yellow, red.
- 5Look at form & habitCrystal system: cubic. Typical habit: dodecahedral and trapezohedral crystals.
Often confused with
Andradite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside andradite
Minerals reported to co-occur with andradite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃Fe₂Si₃O₁₂
- Mohs hardness
- 6.5-7.5
- Density
- 3.8-3.9 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Cubic
- Crystal habit
- Dodecahedral and Trapezohedral Crystals
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Gemstone
- Host rock
- Skarns, Metamorphic Rocks, And Serpentinites
- Typical price
- $10-100 for cabinet specimens, higher for demantoid or top-tier crystals
Where rockhounds find andradite
2 mapped spotsClassic worldwide localities
- Italy
- USA
- Mexico
- Russia
- Namibia
Field-hunting tip
Look in skarns, metamorphic rocks, and serpentinites country — that is the host setting where andradite typically forms. If you start seeing vesuvianite, diopside, magnetite in float, you are in the right ground. Field specimens usually show a dodecahedral and trapezohedral crystals habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Pennsylvania, Utah — start trip planning there.
Common questions
How do you identify andradite?+
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Find andradite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
