Agate
Silicon Dioxide (SiO2)
Category
Browse mineral and sedimentary specimens identified by the Rock Identifier community.
Agate
Silicon Dioxide (SiO2)
Fluorite
Calcium Fluoride (CaF2)
Milky Quartz
Silicon Dioxide (SiO2)
Epidote
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Pyrite-bearing sulfide specimen
Pyrite (FeS₂), possibly mixed with chalcopyrite or other iron sulfides
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Limonite / Ironstone
Hydrated Iron Oxide (FeO(OH)·nH2O)
Sandstone
Clastic Sedimentary Rock (Quartz arenite)
Sandstone
Clastic sedimentary rock (Quartz arenite)
Sandstone
Arenite (Silicon Dioxide with various mineral cements)
Sandstone
Arenite (lithic or quartz sandstone)
Gravel
Unconsolidated rock fragments / detrital sediment
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2)
Sandstone (Banded)
Clastic sedimentary rock (primarily SiO2)
Shale with Siltstone layering
Sedimentary Clastic Rock (Mudstone/Shale)
Sandstone Pebble
Quartzose Sandstone (Sedimentary Rock)
Iron-rich rock or Concretion
Ironstone or Limonite concretion
Sulfur (on Matrix)
Native Sulfur (S8)
Orange calcite pieces on blue calcite or aragonite matrix
Calcite, CaCO₃; blue coloration likely trace-element-bearing calcite (possibly aragonite)
Hematite
Hematite (Fe2O3)
Bornite
Bornite (Cu5FeS4)
Jasper and Agate Mix
Silicon dioxide (SiO2) - Microcrystalline Quartz
Weathered sandstone pebble
Quartz-rich sandstone, commonly arkose or lithic sandstone
Shale
Shale (clastic sedimentary rock)
Quartz Pebble
Silicon Dioxide (SiO2)
Sandstone
Clastic Sedimentary Rock
Shale or Mudstone River Pebble
Argillaceous sedimentary rock
Shale
Shale (clastic sedimentary rock)
Sandstone or Quartzite
Arenite (if sedimentary) / Quartzite (if metamorphic)
Likely metallic mineral specimens
Probably native iron or iron oxide/hydroxide material; exact identification requires testing
Mineral and Rock Collection (Assorted)
Mixed collection including Quartz (SiO2), Jasper (SiO2 with impurities), Rose Quartz, and Aventurine
Quartz fragment
Silicon Dioxide (SiO2)
Hematite
Iron(III) oxide (Fe2O3)
Geode (Quartz / Chalcedony Geode)
SiO2 (Silicon Dioxide)
Gneiss (River Cobble)
Gneiss
Goethite/Hematite Nodule
Goethite (FeO(OH)) and Hematite (Fe2O3)
Druzy Quartz on Ironstone
Silicon Dioxide (SiO2) on Limonitic Ironstone
Sandstone or Mudstone with Iron Staining
Ferruginous Sandstone/Mudstone
Tumbled quartz pebble
Quartz (silicon dioxide, SiO₂), probably milky or iron-stained quartz
Breccia
Sedimentary Breccia
Banded Sandstone (River Cobble)
Arenite Sandstone with heavy mineral layering