Grape Agate is a trade name for botryoidal chalcedony consisting of tiny, tightly packed purple spheres that resemble a bunch of grapes. These distinctive clusters are primarily found in volcanic deposits in Indonesia and are highly prized by collectors for their unique texture and color saturation.
Is this grape agate?
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 grape agate with a known reference. Grape Agate 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. Grape Agate leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Grape Agate typically shows a waxy luster.
- 4Match the color rangeCompare against the expected color range: purple, violet, lavender, white, gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: botryoidal.
Often confused with
Grape Agate vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside grape agate
Minerals reported to co-occur with grape agate. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂
- Mohs hardness
- 6.5-7
- Density
- 2.6 g/cm³
- Streak
- White
- Luster
- Waxy
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Botryoidal
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Decorative
- Host rock
- Volcanic Andesite Cavities
- Typical price
- $10-150 depending on specimen size and cluster density
Where rockhounds find grape agate
1 mapped spotsClassic worldwide localities
- Sulawesi Barat, Indonesia
Field-hunting tip
Look in volcanic andesite cavities country — that is the host setting where grape agate typically forms. If you start seeing calcite, quartz in float, you are in the right ground. Field specimens usually show a botryoidal habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Arizona — start trip planning there.
Common questions
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Find grape agate on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
