sedimentary

Jasper

Jasper (SiO2 plus impurities)

Hardness: 6.5-7 (Mohs); Color: Dark green with reddish-orange veins (iron impurities); Luster: Subvitreous to waxy; Structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91.

Hardness: 6
Color: Dark green with reddish-orange veins (iron impurities)
Luster: Subvitreous to waxy

Identified April 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediments. Over millions of years, the silica crystallizes into microcrystalline quartz. This specimen shows water-worn rounding, suggesting it was part of a riverbed or coastal environment.

Uses & applications

Used primarily for ornamental purposes, jewelry (cabochons), lapidary art, and as a collector's stone. Historically used for making tools due to its sharp conchoidal fracture.

Geological facts

The specific dark green coloration with reddish streaks in stones like this is often referred to as 'Bloodstone' or 'Heliotrope' if the red spots are more distinct, though this specimen is generally classified as a green Jasper with iron-rich veining.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its opaque nature even when held to light, and its very smooth, river-worn texture. Commonly found in gravel pits, riverbeds, and beaches across the Pacific Northwest and other volcanic regions.