Rock Identifier
Snowflake Obsidian and Green Aventurine (Volcanic Glass (SiO2 with Cristobalite inclusions) and Quartz (SiO2 with Fuchsite)) — igneous and metamorphic
igneous and metamorphic

Snowflake Obsidian and Green Aventurine

Volcanic Glass (SiO2 with Cristobalite inclusions) and Quartz (SiO2 with Fuchsite)

AI-generated identification · may be incorrect

Obsidian: Hardness 5-5.5, black with white radial inclusions; Aventurine: Hardness 7, translucent green with aventurescence (sparkly luster), trigonal crystal system.

Identified More igneous and metamorphic →
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Physical properties

Obsidian: Hardness 5-5.5, black with white radial inclusions; Aventurine: Hardness 7, translucent green with aventurescence (sparkly luster), trigonal crystal system.

Formation & geological history

Snowflake Obsidian forms during rapid cooling of silica-rich lava where mineral cristobalite forms small white 'snowflakes'. Green Aventurine is a form of quartzite containing mica, often formed through metamorphism.

Uses & applications

Commonly used for decorative ornaments, jewelry, tumbled stones for collectors, and in metaphysical practices.

Geological facts

The 'snowflakes' in the obsidian are actually internal crystals of the mineral cristobalite. The 'sparkle' in the aventurine is caused by tiny mica inclusions like fuchsite.

Field identification & locations

Both are identified by their distinct inclusions: white bursts in black glass for obsidian, and a shimmering green color for aventurine. Both are common in gift shops and mineral shows.

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Fossilized shell fragment, likely bivalve

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fossil
Fossilized marine shell fragment (Likely a bivalve or gastropod shell preserved as calcite (CaCO₃)) — fossil

Fossilized marine shell fragment

Likely a bivalve or gastropod shell preserved as calcite (CaCO₃)

fossil
Likely quartz-rich stone (possibly milky quartz or quartzite) (Quartz, silicon dioxide (SiO₂), or quartzite if interlocking grains are present) — mineral

Likely quartz-rich stone (possibly milky quartz or quartzite)

Quartz, silicon dioxide (SiO₂), or quartzite if interlocking grains are present

mineral
Granite with Epidote (Granite, containing quartz, feldspar, and epidote) — Igneous

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Biotite Mica Schist (Metamorphic Rock containing Biotite K(Mg,Fe)3AlSi3O10(OH)2) — metamorphic

Biotite Mica Schist

Metamorphic Rock containing Biotite K(Mg,Fe)3AlSi3O10(OH)2

metamorphic
Fossiliferous limestone fragment (Calcitic limestone; mainly calcium carbonate (CaCO₃), possibly with shell or coral debris) — sedimentary

Fossiliferous limestone fragment

Calcitic limestone; mainly calcium carbonate (CaCO₃), possibly with shell or coral debris

sedimentary