Sandstone (Greywacke)
Arenite / Clastic Sedimentary Rock
Category
Browse metamorphic (likely gneiss or schist based on texture) specimens identified by the Rock Identifier community.
Sandstone (Greywacke)
Arenite / Clastic Sedimentary Rock
Precious Opal
Hydrated Silica (SiO2·nH2O)
Granite
Granite (High-silica plutonic rock)
Chert (Pebble)
Microcrystalline silica (SiO2)
Quartz with inclusions (likely Tourmaline or Biotite)
Silicon Dioxide (SiO2)
Sandstone (Quartzite-rich Pebble)
Arenite (composed primarily of SiO2)
Sandstone
Arenite (primarily SiO2)
Fossiliferous Limestone (Chertified Limestone)
Calcium Carbonate (CaCO3) often replaced by Microcrystalline Silica (SiO2)
Granite with Mafic Inclusions
Granite (Phaneritic igneous rock composed of Quartz, Feldspar, and Mica)
Chert (specifically Jasper or Flint)
Cryptocrystalline Quartz (SiO2)
Milky Quartz with Chlorite/Mica inclusions
Silicon Dioxide (SiO2) with phyllosilicate inclusions
Amygdaloidal Basalt
Basalt with secondary amygdule minerals (likely Epidote or Chlorite)
Green Aventurine
Aventurine (variety of Quartz - SiO2)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide - SiO2)
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Volcanic Rock)
Chert (Iron-stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Yellow Quartz (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
Quartzite Pebbles
Quartzite (SiO2)
Pink Granite
Granite (Phaneritic igneous rock)
Chert (Common Opal/Agate inclusion)
Microcrystalline Quartz (SiO2)
Hypersthene
Enstatite (Hypersthene variety), (Mg,Fe)SiO3
River Pebble (Greywacke or Basaltic)
Massive Greywacke or Basaltic Andesite
Granite
Granite (composed primarily of Quartz, Feldspar, and Mica)
Emerald
Beryl (Be₃Al₂Si₆O₁₈), specifically the green variety colored by trace amounts of chromium or vanadium.
Basalt
Basalt
Quartz (Milky/Iron-stained)
Silicon Dioxide (SiO2)
Basalt
Mafic volcanic rock (Basalt)
Banded Chert (Flint)
Microcrystalline Quartz (SiO2)
Orange Calcite (likely polished specimen)
Calcite
Chert (variations include Chalcedony and Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (often called Flint or River Stone)
Chert (SiO2)
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
River Pebble Gravel
Hydrothermally modified Clastic Sediment (mainly Quartzite and Chert)
Epidote
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
Amazonite
KAlSi3O8 (Potassium aluminum silicate - blue-green variety of Microcline)
Quartz (Milky Quartz with Iron Staining)
Silicon Dioxide (SiO2)
Sandstone (with carbonaceous plant fragments)
Arenite (composed primarily of SiO2)
Jasper (with Agate/Chalcedony inclusions)
Silicon Dioxide (SiO2)
Chert (Arrowhead Fragment)
Chert / Microcrystalline Silicon Dioxide (SiO2)
Granite (Weathered)
Phaneritic Plutonic Rock (primarily Quartz, Feldspar, and Mica)
Granite (specifically Pink Granite)
Phaneritic Plutonic Rock (High Potassium Feldspar Granite)