Blue Lace Agate
Chalcedony (cryptocrystalline variety of Quartz), SiO2
mineral
Category
Sedimentary (Volcanic)
Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.
Tiffany Stone
Fluoritized Opal Beryllium Ore (principally Bertrandite, Be4Si2O7(OH)2)
metamorphic
Rough Diamond
Diamond (Native Element Carbon, C)
mineral
Obsidian (Arrowhead Lithic Tool)
Obsidian (Amorphous Volcanic Glass / SiO2 + inclusions)
igneous
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)
igneous
Carnelian
SiO2 (Silicon Dioxide) - Carnelian variety of Chalcedony
mineral
Green Glass (often marketed as 'Obsidian' or 'Green Quartz')
Amorphous Silica (SiO2) with copper or chromium additives
Mineraloid (Man-made)
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide SiO2)
Igneous
Basalt (with possible weathering or secondary mineral crust)
Basalt (Aphanitic Mafic Igneous Rock)
Igneous
Sandstone (Ferruginous)
Arenite (Fe2O3 rich)
sedimentary
Coarse Sandstone
Arenite (SiO2 based)
sedimentary
Hematite
Hematite, Iron(III) oxide (Fe2O3)
mineral
Puddingstone (Jasper Conglomerate)
Conglomerate (specific type: Jasper Conglomerate or Hertfordshire Puddingstone)
Sedimentary
Barite Rose on Marcasite
Barium Sulfate (BaSO4) on Iron Sulfide (FeS2)
mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (likely Arkosic)
Clastic Sedimentary Rock (Sandstone)
sedimentary
Sandstone (Ferruginous)
Clastic Sedimentary Rock (Litharenite)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with Ferric Hydroxide impurities
mineral
Basalt
Mafic volcanic rock (various silicate minerals including Pyroxene and Plagioclase)
igneous
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sedimentary Rock
Scoria (Lava Rock)
Aphanitic vesicular mafic igneous rock
igneous
Vesicular Basalt (Scoria)
Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
igneous
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Geode (unopened) or Calcareous Nodule
Siliceous or Calcareous Concretion/Nodule
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (Tumbled/River Pebble)
Arenite (composed primarily of SiO2)
sedimentary
Basalt
Extrusive mafic igneous rock
igneous
Petrified Wood
Silicified Wood / Chalcedony (SiO2)
mineral
Agate
Silicon Dioxide (SiO2) - Variety of Chalcedony
mineral
Basalt (River Pebble)
Extrusive Mafic Igneous Rock
igneous
Olivine (Peridotite)
(Mg,Fe)2SiO4 (Magnesium Iron Silicate)
igneous
Basalt Pebble
Extrusive Mafic Igneous Rock
igneous
Petrified Wood
Silicified Wood (SiO2 - Quartz/Chalcedony replacement)
Mineral / Fossil
Obsidian (Gold Sheen)
Obsidian (SiO2 + impurities)
igneous
Carnelian (Orange Chalcedony)
Silicon dioxide (SiO2)
mineral
Porphyry
Porphyritic Basalt or Porphyritic Andesite
igneous
Basalt with Quartz Veining
Amygdaloidal Basalt (predominately SiO2 and (Na,Ca)(Si,Al)4O8)
igneous
Granitic Pegmatite with Schorl
Granitic Pegmatite (NaAlSi3O8, KAlSi3O8, SiO2) with Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
igneous
Agate
Cryptocrystalline Quartz (SiO2)
mineral
Greenstone (Amygdaloidal Basalt)
Amygdaloidal Basalt (frequently composed of Plagioclase Feldspar, Pyroxene, and Olivine with Chlorite inclusions)
igneous
Vesicular Basalt
Extrusive mafic igneous rock; primarily (Ca,Na)(Mg,Fe,Al,Si)2O6 (Pyroxene) and (Ca,Na)Al(Al,Si)Si2O8 (Plagioclase Feldspar)
igneous