Sand Grain (Quartz / Feldspar)
Silicon dioxide (SiO2) or Potassium Feldspar (KAlSi3O8)
mineral
Category
Igneous And Metamorphic
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Quartz pebble
Silicon dioxide (SiO2)
sedimentary
White Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Blue Sapphire
Corundum (Al2O3)
gemstone
Magnetite
Fe3O4
mineral
Yellow Quartz (Citrine Quartz / Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Biotite
K(Mg,Fe)_3AlSi_3O_10(OH,F)_2
mineral
Tourmaline
Complex boron silicate, (Na,Ca)(Al,Fe,Li)_3Al_6(BO_3)_3Si_6O_18(OH)_4
mineral
Citrine
Silicon Dioxide (Quartz variety)
gemstone
Galena
Lead Sulfide (PbS)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Mixed Mineral and Crystal Assortment
Various silicate and oxide minerals
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Yellow Citrine
Silicon Dioxide (Quartz variety), SiO2
mineral
Peacock Ore
Bornite (Cu5FeS4)
mineral
Quartz pebble
Silicon dioxide (SiO2)
mineral
Quartz pebble
Silicon dioxide (SiO2)
mineral
Quartz pebble
Silicon dioxide (SiO2)
mineral
Strawberry Quartz (Quartz with Hematite inclusions)
Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3)
mineral
Strawberry Quartz
Quartz with Hematite inclusions (SiO2 + Fe2O3)
mineral
Feldspar
Feldspar Group (Tectosilicate, e.g., KAlSi3O8)
mineral
Biotite Mica
Biotite (K(Mg,Fe)3(AlSi3O10)(F,OH)2)
mineral
Carnelian Agate
Silicon Dioxide (Chalcedony variety), SiO2
gemstone
Epidote
Ca2(Al,Fe)3(SiO4)3(OH)
mineral
Biotite on Matrix
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)
mineral
Tumbled Sunstone
Feldspar group (Oligoclase)
gemstone
Epidote
Ca2(Al,Fe)3(SiO4)3(OH)
mineral
Quartz pebble
Silicon dioxide (SiO2)
mineral
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
mineral
Citrine
Silicon dioxide (SiO2)
mineral
Amethyst Geode/Cluster
Quartz (SiO2) - variety Amethyst
Mineral
Black Tourmaline (Schorl)
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
White Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Blue Quartz
Silicon Dioxide (SiO2) with inclusions
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Small rough mineral fragment, possibly quartz or feldspar
Unidentified silicate mineral; image is insufficient for a reliable species identification
mineral
Citrine or Yellow Sapphire
Quartz (SiO2) or Corundum (Al2O3)
gemstone