Sandstone (likely Arkosic or Lithic Sandstone)
Arenite (SiO2 based with mineral inclusions)
sedimentary
Category
Synthetic (Man Made Glass)
Browse synthetic (man made glass) specimens identified by the Rock Identifier community.
Obsidian
Volcanic glass (mainly SiO2)
Igneous
Black Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Pumice
Pumice (Vesicular Volcanic Glass)
igneous
Tektite (specifically Indochinite)
Tektite (Natural silica glass)
Mineraloid (Impact glass)
Pumice
Pumice (volcanic glass foam)
igneous
Slag
Anthropogenic Iron Silicate Glass
mineral
Pumice
Pumice (Vesicular volcanic glass)
igneous
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Pumice
Pumicite (Amorphous volcanic glass)
Igneous
Apache Tear
Hydrated Obsidian (Volcanic Glass)
igneous
Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Igneous
Obsidian
Obsidian (Amorphous volcanic glass)
igneous
Apache Tear (Obsidian)
Volcanic glass / Amorphous SiO2
igneous
Apache Tear
Obsidian (Hydrated Volcanic Glass)
igneous
Obsidian (specifically Rainbow or Silver Sheen Obsidian)
Volcanic Glass (predominantly SiO2)
Igneous
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
igneous
Apache Tear
Hydrated Obsidian (Volcanic Glass)
Igneous
Pumice
Pumice (Amorphous volcanic glass)
igneous
Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
sedimentary
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
igneous
River Quartz Cobble
Silicon Dioxide (SiO2)
mineral
Quartz (Milky/Iron-stained)
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz (Gravel Pebble)
Silicon Dioxide (SiO2)
mineral
Quartz in Matrix
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Feldspar
KAlSi3O8 - NaAlSi3O8 - CaAl2Si2O8
mineral
Obsidian
Volcanic Glass (SiO2 rich)
igneous
Chert (Gravel Bit)
Microcrystalline silica (SiO2)
sedimentary
Fulgurite
Lechatelierite (Silica glass), typically SiO2
mineraloid
Quartz (Sea Glass or River-worn Pebble style)
Silicon Dioxide (SiO2)
mineral
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Igneous
Sandstone (likely Quartzose Sandstone)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary