How to identify Ocean Jasper

To correctly identify Ocean Jasper (Orbicular Jasper (a variety of Chalcedony)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Extremely variable, including shades of green, yellow, brown, red, cream, white, pink, and occasionally blue. Often multi-colored within a single specimen.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous to waxy, dull on unpolished surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically smooth and fine-grained when polished. Unpolished surfaces can be slightly rough or granular.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cryptocrystalline, meaning individual crystals are microscopic and not visible to the naked eye. Forms botryoidal, mammillary, or nodular masses with characteristic orbicular patterns.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None, due to its cryptocrystalline nature.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins and infillings within rhyolitic volcanic rocks, particularly those formed in coastal or submarine environments. Often found as nodules or seams within altered volcanic tuffs and flows.

Key Facts

Hardness

6.5-7 on the Mohs scale

Specific Gravity

2.58-2.64

Crystal System

Trigonal (cryptocrystalline aggregates)

Color

Highly variable; green, yellow, red, brown, cream, white, pink, blue, often multi-colored with orbicular patterns.

Luster

Vitreous to waxy, dull on unpolished surfaces.

Transparency

Opaque to translucent.

Fracture

Conchoidal to uneven.

Cleavage

None.

Composition

Silicon dioxide (SiO2) with various mineral inclusions.

Physical characteristics

• Crystal Habit: Cryptocrystalline aggregates forming botryoidal, mammillary, or nodular masses with characteristic orbicular structures.
• Cleavage Type: Absent.
• Fracture Type: Conchoidal to uneven, splintery.
• Tenacity: Brittle.
• Luster Type: Vitreous to waxy.

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