Rock Identifier
Polished Ocean Jasper (Silicon Dioxide (Chalcedony/Quartz), SiO2) — gemstone
gemstone

Polished Ocean Jasper

Silicon Dioxide (Chalcedony/Quartz), SiO2

Hardness of 6.5 to 7 on the Mohs scale, multicolored patterns including red, green, yellow, and white orbs or cellular structures, waxy to vitreous luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no true cleavage, specific gravity around 2.58 to 2.64.

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Physical properties

Hardness of 6.5 to 7 on the Mohs scale, multicolored patterns including red, green, yellow, and white orbs or cellular structures, waxy to vitreous luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no true cleavage, specific gravity around 2.58 to 2.64.

Formation & geological history

Formed as silica-rich hydrothermal fluids or volcanic ash rich in silica filled cavities in rhyolitic lava flows. It crystallizes into spherulites of chalcedony. Primarily found in Madagascar along the northwestern coast.

Uses & applications

Used widely for ornamental lapidary work, cabochons for jewelry, carved decorative objects, and highly sought after by mineral collectors.

Geological facts

Ocean Jasper is famous for its distinct 'orby' patterns and multicolor combinations. True ocean jasper is mined in a remote coastal location in Madagascar that can often only be accessed at low tide by boat.

Field identification & locations

Easily identified by its distinctive multicolored spherulitic or orbicular patterns embedded in a microcrystalline quartz matrix. Collectors seek out high contrast patterns with clear, well-defined orbs and vibrant colors.