Granite
Granitic intrusive igneous rock
Category
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Granite
Granitic intrusive igneous rock
Nuummite
Nuummite (intergrowth of orthoamphiboles Anthophyllite and Gedrite, (Mg,Fe)7Si8O22(OH)2)
Greenstone / Epidosite
Epidosite (Metasomatic rock consisting mainly of Epidite Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH) and Quartz)
Sandstone (Red Arkose)
Sandstone (Arkose variant, primarily SiO2 with KAlSi3O8)
Granite Pebble
Granite (a plutonic igneous rock composed primarily of quartz, feldspar, and mica/amphibole)
Basalt
Basalt (dominated by plagioclase feldspar and pyroxene)
Sandstone
Arenite (primarily SiO2 - Silicon Dioxide)
Rhodonite Tumbled Chips
Manganese silicate (Mn,Fe,Mg,Ca)SiO3
Carnelian
Carnelian (subset of Chalcedony); SiO2 with Iron Oxide impurities
Moonstone
Orthoclase (KAlSi3O8) with inclusions of Albite (NaAlSi3O8)
Milky Quartz
Silicon Dioxide (SiO2)
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide staining)
Citrine Quartz
Silicon Dioxide (SiO2)
Granite
Granite (Felsic Plutonic Rock)
Diamond (in jewelry setting)
Adamantine Carbon (C)
Yellow Quartz (Citrine Quartz Pebble)
Silicon Dioxide (SiO2)
Sandstone
Arenite (primarily SiO2, silica)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
Granite
Granite (a felsic intrusive igneous rock)
Orthoclase Feldspar (Salmon variety)
Orthoclase, KAlSi3O8
Sandstone (Pebble/Cobble)
Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)
Vesicular Basalt
Mafic Volcanic Rock (Basalt)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Iron Oxide cement)
Quartz Geode in Chert/Limestone Matrix
Silicon Dioxide (SiO2) within Sedimentary Host Rock
Jasper
Cryptocrystalline Quartz (SiO2)
Pumice
Pumice (volcanic rock)
Jasper (Picture Jasper variety)
Silicon Dioxide (SiO2) with impurities
Green Chalcedony (likely Green Agate or Chrysoprase)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Quartz Pebble
Silicon Dioxide (SiO2)
Greenschist
Greenschist facies rock (containing chlorite, actinolite, and epidote)
Red Shale
Fissile Siliciclastic Sedimentary Rock
Man-made Metal Pin (Non-geological)
Antimony-Lead Alloy or Zinc/Brass Base with Electroplating
Septarian Nodule Segment (Turtle Stone)
Septarian Concretion (CaCO3 with Siderite or Calcite infill)
Amber
Fossilized Tree Resin (Generic formula roughly C10H16O)
Diamond
Carbon (C)
Sandstone (with Iron Oxide)
Arenite with Limonite/Hematite staining
Quartz (Milky or Smoky variety)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Chalcedony (Botryoidal or Agate nodule)
Silicon Dioxide (SiO2)
Amethyst
Amethyst (Silicon Dioxide, SiO2 with Iron impurities)
Sandstone with Liesegang Rings
Arenite with Iron Oxide Liesegang Banding