Ocean Jasper
Volcanic & Glassy Family
Ocean Jasper is a trade name for orbicular ornamental rock from coastal northwestern Madagascar. Despite the name, it is not strictly jasper: the material is highly silicified rhyolite or tuff in which radial quartz and feldspar aggregates create rounded spots and rings.
Identity
- Material or variety
- Jasper (opaque microcrystalline quartz)
- Scientific or material identity
- Jasper (opaque microcrystalline quartz)
- Classification
- Rock or mixed mineral material
- Aliases or trade names
- Orbicular jasper · Madagascar orbicular jasper
- Composition or formula
- SiO₂ with mineral inclusions
- Crystal system or structure
- Aggregate or composite structure
- Geological or manufacturing origin
- Can form in more than one geological environment, or combines several materials.
- Mohs hardness
- 6.5 to 7
- Specific gravity
- 2.58 to 2.91
Origins
Marovato, Madagascar · Kabamby, Madagascar
Appearance & optical properties
green and cream rhyolite with round orbicular spots.
History & discovery
The trade name refers to material found near the coast around Marovato in Madagascar’s Analalava District. Mineral records identify that restricted source as orbicular quartz or silicified volcanic rock rather than a separate mineral species. The ocean reference describes the coastal source, not a marine origin for the rock.
Uses & care
- Common uses
- Its colorful circular patterns are displayed in polished slabs, jewelry cabochons, beads, spheres, small carvings, decorative objects, and collector specimens.
Jewellery
5 pieces of Ocean Jasper jewellery. Learners earn each one in DigMyGem by learning words; until then it shows as a silhouette.
Tidepool Pendant
Pendant
An oval ocean jasper hangs from a silver loop, its green, cream and pink orbs like pools left by the tide.
Reef Ring
Ring
A round ocean jasper cabochon sits in a white-gold band, its ringed dots reading as coral heads in still water.
Shoreline Bracelet
Bracelet
Flat ocean jasper links run along a silver chain, each stone showing a different little seascape.
Orbicular Sea Brooch
Brooch
An imagined brooch of ocean jasper from the coast of Madagascar, whose round eye-like orbs look like bubbles in a tide pool.
Tidepool Tiara
Tiara
An imagined silver tiara of shells and waves set with ocean jasper, whose round eyes look like bubbles in a tidepool.