Iron-rich weathered rock or limonite/goethite nodule
Limonite (mixture dominated by goethite, FeO(OH)·nH₂O), possibly with quartz or clay
Category
Browse man made byproduct (non geological) specimens identified by the Rock Identifier community.
Iron-rich weathered rock or limonite/goethite nodule
Limonite (mixture dominated by goethite, FeO(OH)·nH₂O), possibly with quartz or clay
Native Silver
Silver (Ag)
Quartzite
Metamorphic rock (SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Obsidian
Volcanic glass (primary composition: SiO2)
Obsidian
Volcanic Glass
Obsidian
Amorphous volcanic glass (principally SiO2)
Polished quartz-rich pebble, possibly jasper or quartzite
Quartzite or chalcedony-bearing jasper; predominantly SiO₂
Amethyst
Silicon Dioxide (SiO2) with Fe3+ impurities
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Banded Sandstone (Liesegang Rings)
Sedimentary sandstone with Iron oxide precipitates
Anthracite Coal
Anthracite
Quartzite
Quartzite (chiefly SiO2)
Quartzite
Metamorphic Quartz Rock (SiO2)
Black Obsidian
Obsidian (Volcanic Glass, ~70% SiO2)
Black Obsidian
Obsidian (Volcanic Glass, rich in SiO2)
Obsidian
Volcanic Glass (SiO2)
Serpentinite
Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)
Diamond
Carbon (C)
Raw greenish crystal/mineral fragment
Uncertain from image; possibly olivine (forsterite-rich), epidote, or green tourmaline
Quartzite
Quartzite (primarily SiO2)
Obsidian
Volcanic Glass (SiO2)
Snowflake Obsidian
Spherulitic Obsidian (Volcanic Glass with Cristobalite inclusions)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Snowflake Obsidian
Volcanic glass containing Cristobalite (SiO2)
Quartzite
Quartzite (SiO2)
Quartzite
Quartzite (primarily SiO2)
Bull Quartz
Quartz (Silicon Dioxide - SiO2)
Pyrite
Iron Disulfide (FeS2)
Obsidian
Obsidian (Volcanic glass), 70-75% SiO2
Diamond
Carbon (C)
Quartzite
Metamorphic Quartzite (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Quartzite
Metamorphic Quartzite (primarily SiO2)
Quartzite
Quartzite (primarily SiO2)
River Siltstone / Mudstone Pebble
Siltstone (composed of mixed silicate and carbonate minerals)
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Limonite (Yellow Ochre)
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
Rough Green Beryl (Emerald variety)
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
Red Jasper
Microcrystalline Quartz (SiO2) with Hematite impurities
Quartz-rich conglomeratic sandstone
Lithic arkose/conglomerate, dominated by quartz and feldspar grains