Diamond
C (Carbon)
mineral
Category
Mineraloid (Man Made Origin)
Browse mineraloid (man made origin) specimens identified by the Rock Identifier community.
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Basalt Cobble
Aphanitic Mafic Igneous Rock (Basalt)
igneous
Corundum
Corundum (Aluminium oxide, Al2O3)
mineral
Crushed Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Vesicular Basalt (Aqueous Tumbled)
Scoriaceous Basalt
igneous
Black Pearl (Tahitian Pearl)
Aragonite / Calcite (CaCO3) with Conchiolin
mineral
Opal
Hydrated Silica (SiO2·nH2O)
mineral
Limonite (Ironstone)
Limonite (mixture of hydrated iron(III) oxide-hydroxides)
mineral
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)
mineral
Obsidian
Volcanic Glass (SiO2)
igneous
Mixed Mineral and Fossil Collection
Multi-specimen assemblage (SiO2, CaCO3, FeS2, etc.)
mineral
Asphalt (Bituminous Pavement Bit)
Bitumen-bound aggregate (Petrochemical-bound composite)
sedimentary (anthropogenic/technogenic)
Blue Sapphire
Corundum (Al2O3 with iron and titanium trace elements)
mineral
Given the appearance, it's likely a fragment of an igneous or metamorphic rock composed of multiple minerals. Without specific diagnostic features, it's difficult to give a common name other than 'crystalline rock fragment'. If pressed to guess based on the granular, somewhat light and dark speckled appearance, it could be a fragment of granite or a related intrusive igneous rock.
As a rock fragment, it does not have a single scientific mineral name; rather, it's a piece of a rock which is a combination of minerals. If it were granite, its main mineral composition would be quartz (SiO2), feldspar (e.g., KAlSi3O8 - orthoclase, (Na,Ca)(Al,Si)4O8 - plagioclase), and mica (e.g., KAl2(AlSi3O10)(OH)2 - muscovite or K(Mg,Fe)3AlSi3O10(OH)2 - biotite), among others.
Mineral, possibly rock fragment containing a mineral
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Mineral (Organic Gemstone)
Kambaba Jasper
Stromatolite (Fossilized Algae within Microcrystalline Quartz)
sedimentary
Chert (Black Chert)
Microcrystalline Silica (SiO2)
sedimentary
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Fluorite (Purple variety)
Calcium Fluoride (CaF2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Cardstock (Paper)
Cellulose (C6H10O5)n
sedimentary (man-made)
Blue Slag Glass
Amorphous Silica (Byproduct of smelting)
Antropogenic (Man-made)
Blue Goldstone
Aventurine Glass (SiO2 with Cobalt/Copper inclusions)
man-made glass
Slag Glass (Cullet)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Anthropogenic (Man-made)
Slag (Anthropogenic Glass/Iron byproduct)
Ferro-silicate Slag
Anthropogenic (Man-made)
Artisanal Glass Beads (Simulated Goldstone or Aventurine Glass)
Silicon Dioxide (SiO2) with metallic inclusions
man-made material
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2)
igneous
Limonite (Yellow Ochre)
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
mineral
Black Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Limonite (Yellow Ochre)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
mineral
Limonite/Goethite Concretion
Hydrated Iron(III) Oxide-hydroxide (FeO(OH)·nH2O)
sedimentary
Obsidian
Obsidian (Volcanic Glass)
igneous
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
mineraloid
Common Opal
Hydrated Amorphous Silica (SiO2·nH2O)
mineraloid
Limonite (Ironstone)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
mineral
Limonite (Iron Ore)
Limonite (Hydrated iron oxide - FeO(OH)·nH2O)
mineral
Limonite (Iron Stone/Goethite)
Limonite (mixture of hydrated iron oxides, primarily Goethite: α-FeO(OH))
mineral
Blue John Fluorite
Fluorite (Calcium Fluoride), CaF2
mineral
Basalt (Weathered Pebble)
Basalt (Mafic Extrusive Igneous Rock)
igneous
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral