$490Median
3488Sold (12 mo)
$125Last sale
Quartz
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Rounded botryoidal purple crystallized quartz in a cluster without matrix.Mamuju, located on the western coast of Sulawesi Island in Indonesia, is the primary source of the material widely marketed under the trade name grape agate. Geologically, the deposits are situated within volcanic and hydrothermal environments, where silica-rich fluids filled cavities and gas bubbles in ancient lava flows, precipitating mineral layers within altered clay pockets. Mineralogically, despite its popular moniker, the material is not a true banded agate; rather, it consists of spherical, botryoidal clusters of tiny microcrystalline quartz crystals (often purple amethyst or soft green varieties colored by trace inclusions). Historically, mining in the remote, rugged terrain around Mamuju began around 2014, and the distinctive spherical specimens burst onto the international mineral market around 2016, quickly becoming a global favorite among collectors.
Product details
SpeciesQuartz
SizeThumbnail
Dimensions2.5 x 2.0 x 2.0 cm
Added on09/05/2026
LocalityIndonesia, West Sulawesi Province, Mamuju Regency
Current owner
Unknown Owner
Previous owners
| Date | Collector | Acquisition price |
|---|---|---|
| — | Weinrich Minerals | Not disclosed |
Learn more
Mineral guide
Learn about Quartz
a versatile mineral with clear, milky, and colored varieties; crystal forms, formation clues, and tips for identifying amethyst and citrine.Regional guide
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