Exotic River Agate from Sumatra – Polished Half (Indonesia)
This specimen is a natural river agate from Sumatra—one of Indonesia’s most geologically diverse islands. Local agates formed in volcanic rocks under tropical conditions and were subsequently dislodged from their host rock and carried away by rushing mountain rivers. The process of natural water erosion gave the agate the rounded shape of a river pebble. The front surface has been polished to a mirror-like shine, revealing the precise banding of the chalcedony and a unique, deep palette of colors.
Specimen details:
- ✓ Stone: River agate (polished half / pebble)
- ✓ Origin: Indonesia, Sumatra
- ✓ Formation environment: River sediments (water transport)
- ✓ Finish: Front surface flat-polished to a high gloss, back rough (rounded pebble)
- ✓ Dimensions: approx. 125 × 39 × 45 mm
- ✓ Weight: approx. 263 g
- ✓ Unique: The item offered is exactly the specimen shown in the photos
A testament to tropical geological processes
Sumatra is famous for its minerals with extraordinary color variations, which are due to volcanic rocks rich in iron and other trace elements. River agates from this region are highly prized for their hardness and the smoothness of their natural, rough exterior, formed by the river’s current. The contrast between the matte, natural outer surface and the perfectly polished, crystalline interior makes this specimen look exceptionally striking on a collector’s shelf or in a display case.
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