Pumice
Pumice (volcanic rock)
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Pumice
Pumice (volcanic rock)
Carnelian (Orange Agate)
Silicon Dioxide (SiO2)
Jasper (Iron-stained Chalcedony)
SiO2 with Fe2O3 (Iron Oxide) impurities
Petrified Wood
Silicified Wood (SiO2)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Shale (possibly)
Shale (fine-grained clastic sedimentary rock)
Amber
Succinite (fossilized tree resin)
Quartz (Milky or Common Quartz)
Silicon Dioxide (SiO2)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Quartz (Milky or Rough Quartz)
Silicon Dioxide (SiO2)
Chert (Flint variety)
Silicon Dioxide (SiO2)
Chert (Polished River Pebble)
Chert (SiO2)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) in Rhyolitic Matrix
Jasper and Quartzite Pebble
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Citrine Quartz
Silicon Dioxide (SiO2)
Quartz (Milky/Smoky variety on matrix)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily Silicon Dioxide, SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (and Flint)
Chert (SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Glauconitic Sandstone
Glauconitic Sandstone (contains (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Carnelian Agate
Silicon Dioxide (SiO2) - Variety of Chalcedony
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Mixed Gemstone Bracelet
Mixed natural minerals and rocks (e.g., Rhodonite, Malachite, Sodalite, Rose Quartz, Black Tourmaline, Quartz/Chalcedony variants)
Sphalerite with Galena
Zinc Sulfide ((Zn,Fe)S) and Lead Sulfide (PbS)
Pearl
Organic Mineral (CaCO3 with conchiolin)
Fancy Jasper
Chalcedony (cryptocrystalline quartz) with inclusions
Chert (Nodule)
Silicon Dioxide (SiO2)
White Quartz (Milky Quartz)
Quartz (Silicon Dioxide, SiO2)
Jasper Agate
Silicon dioxide (SiO2)
Mother of Pearl and Onyx
Aragonite (Mother of Pearl) and Chalcedony (Onyx)
Diorite
Intermediate plutonic igneous rock
Rhodonite
Rhodonite (MnSiO3)
Red Porphyry
Porphyritic Andesite or Rhyolite
Granite
Granite (Felsic Plutonic Rock)
Quartz (Clear/White)
Silicon Dioxide (SiO2)
Fossilized Wood (Petrified Wood)
Silicified Wood (primarily quartz/chalcedony replacing organic matter)
Quartz Geode (Nodule)
Silicon Dioxide (SiO2)
Gold-Bearing Quartz
Auriferous Quartz (SiO2 with native Au)
Blue Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)