igneous
Green Porphyry (Flowerstone)
Porphyritic Andesite or Basalt
Hardness: 6-7 on Mohs scale; Color: Dark green matrix with lighter green or white phenocrysts; Luster: Dull to sub-vitreous; Crystal structure: Aphanitic matrix with large visible crystals (phenocrysts); Specific gravity: 2.5-3.0
- Hardness
- 6-7 on Mohs scale
- Color
- Dark green matrix with lighter green or white phenocrysts
- Luster
- Dull to sub-vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Dark green matrix with lighter green or white phenocrysts; Luster: Dull to sub-vitreous; Crystal structure: Aphanitic matrix with large visible crystals (phenocrysts); Specific gravity: 2.5-3.0
Formation & geological history
Formed from volcanic activity where magma cooled in two stages: first slowly deep underground (forming the large crystals) and then rapidly near the surface (forming the fine-grained matrix). Often associated with Mesozoic volcanic arcs.
Uses & applications
Used primarily as decorative stone, for lapidary work (cabochons), as garden 'pocket stones', and historically in construction or as dimension stone.
Geological facts
Also known as 'Flowerstone' due to the flower-like appearance of the lighter crystals. Ancient Romans highly prized a similar variety called 'Lapis Lacedaemonius' from Greece for imperial decor.
Field identification & locations
Identify by looking for distinct, lighter-colored 'spots' or crystals embedded in a dense, darker green fine-grained rock. Commonly found on beaches in the Pacific Northwest (specifically Vancouver Island) and Greece.
