igneous
Porphyritic Basalt (Chinese Writing Stone/Flower Stone)
Porphyritic Basalt (primarily Plagioclase Feldspar in a Mafic groundmass)
Hardness: 6.0-6.5 (Mohs); Color: Black or dark grey matrix with white or cream inclusions; Luster: Dull to sub-vitreous; Crystal Structure: Amorphous/Fine-grained matrix with lath-like phenocrysts; Specific Gravity: 2.8–3.0.
- Hardness
- 6
- Color
- Black or dark grey matrix with white or cream inclusions
- Luster
- Dull to sub-vitreous
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Physical properties
Hardness: 6.0-6.5 (Mohs); Color: Black or dark grey matrix with white or cream inclusions; Luster: Dull to sub-vitreous; Crystal Structure: Amorphous/Fine-grained matrix with lath-like phenocrysts; Specific Gravity: 2.8–3.0.
Formation & geological history
Formed from slow cooling of basaltic magma underground followed by rapid cooling at the surface. This specimen appears water-worn (tumbled), suggesting an origin in a riverbed or coastal environment from the Mesozoic or Cenozoic eras.
Uses & applications
Commonly used for lapidary work (cabochons), jewelry, decorative landscaping, and as pocket stones for collectors.
Geological facts
This specific variety is often marketed as 'Chinese Writing Stone' or 'snowflake stone' because the feldspar inclusions resemble brush strokes or calligraphic characters. The white 'letters' are actually plagioclase feldspar crystals that grew during the early cooling phase of the magma.
Field identification & locations
Identify by looking for white rectangular or lath-shaped crystals embedded in a dark, fine-grained rock. Common in volcanic regions such as the Pacific Northwest of the USA, British Columbia, and China. Collectors should look for high contrast between the dark matrix and white crystals.
