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

Identified March 29, 2026More igneous →

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Physical properties

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.

Other igneous specimens

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral