Anthracite Coal
Anthracite (Carbon ≥ 86%)
sedimentary
Category
Mineraloid Like Synthetic Material
Browse mineraloid like synthetic material specimens identified by the Rock Identifier community.
Learn about Mineraloid Like Synthetic Material in the encyclopedia
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Emerald
Beryl (Be3Al2Si6O18), specifically the green variety colored by chromium or vanadium
Mineral (Gemstone variety of Beryl)
Yellow Sapphire
Corundum (Al2O3:Fe)
gemstone
Citrine
Citrine (Silicon Dioxide, SiO2)
mineral
Smoky Quartz
Smoky Quartz (Silicon Dioxide - SiO2)
mineral
Smoky Quartz (with Druzy/Polished Edge)
Smoky Quartz (Silicon Dioxide, SiO2)
mineral
Limestone
Sedimentary rock composed mainly of calcium carbonate (CaCO3)
sedimentary
Sandstone
Arenite (SiO2 primarily)
sedimentary
Carved Stone Turtle
Carved Soapstone and Quartz
mineral
Red Sandstone
Arenite (Iron-rich)
sedimentary
Sandstone
Arenite
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Sandstone
Arenite (primarily SiO2 with Fe2O3)
sedimentary
Petrified Wood (Silicified Fossil)
Silicified Wood (SiO2)
sedimentary
Opal
Hydrated amorphous form of silica (SiO2·nH2O)
mineral
Sandstone
Arenite (primary component SiO2)
sedimentary
Drupa or Druzy Quartz on Geode Fragment
Crystalline Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of organic matter)
sedimentary
Opalite
Synthetic Glass (typically Silica/Magnesium based with metal additives)
mineral
Coquina
Biogenic Limestone (mostly Calcium Carbonate, CaCO3)
sedimentary
Diamond (Faceted)
Diamond (Pure Carbon, C)
gemstone
Asphalt Chunk
Asphalt concrete
man-made composite
Oak-grain Laminate (Industrial/Decorative Furniture Finish)
Melamine Resin-impregnated Decorative Paper on Particleboard (Cellulose/Thermosetting Plastic)
not a rock (synthetic material)
Hematite
Iron(III) oxide (Fe2O3)
mineral
Corundum
Corundum (Al2O3)
Mineral
Diamond (Rough)
Diamond (Carbon, C)
Mineral
Plume Agate or Moss Agate
Agate (SiO2)
mineral
Sandstone
Arenite (SiO2 with various cementing agents)
sedimentary
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sedimentary Rock
Red Sandstone
Arenite (SiO2 with Fe2O3)
sedimentary
Sandstone (with concrete/human-made layer)
Clastic Sedimentary Rock (primarily Quartz/Feldspar grains)
sedimentary
Geode with Quartz/Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
igneous
Plum Blossom Tourmaline
Tourmaline with Lepidolite (Na,Ca)(Li,Mg,Al)3Al6(BO3)3Si6O18(OH)4
igneous
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Coquina
Coquina (Bioclastic Limestone)
sedimentary
Limestone and Quartz Gravel with Petrified Wood
Sedimentary gravel aggregate and fossilized wood
sedimentary
Coquina
Biogenic Limestone (Calcite, CaCO3)
sedimentary
Orbicular Granite (specifically Mustard or Yellow Tonalite/Granodiorite)
Orbicular Quartz Diorite / Tonalite
igneous
Polished amber
Amber (fossilized plant resin), commonly succinite; organic mineraloid rather than a true mineral
gemstone
Coquina
Bioclastic Limestone
sedimentary