Polished amethyst crystal point
Amethyst, purple quartz (SiO₂)
mineral
Category
Organic Gem Material (Botanical)
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Coarse Sand or Fine Gravel
Detrital Sedimentary Fragments (mostly SiO2)
sedimentary
Tumbled dark green stone, likely greenstone/serpentinite
Serpentinite (serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄), possibly chlorite-rich greenstone
metamorphic
Sugilite
Sugilite (KNa2(Fe,Mn,Al)2Li3Si12O30)
mineral
Quartz-veined Limestone
Sedimentary limestone with quartz/calcite veinlets
sedimentary
Clear quartz (likely)
Quartz, SiO₂
gemstone
Tumbled rhodonite
Rhodonite, manganese inosilicate (MnSiO₃)
mineral
Likely limestone or chalky carbonate rock
Calcite-rich carbonate rock; chiefly calcium carbonate (CaCO₃)
sedimentary
Sandstone
Sandstone (Quartz-rich Arenite / SiO2)
sedimentary
Poppy Jasper
Microcrystalline Quartz (SiO2) with hematite and other inclusions
sedimentary
Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Sandstone
Arenite (SiO2 composed primarily of quartz)
sedimentary
Chert / Flint
Silicon dioxide (SiO2)
sedimentary
Chert (Yellow Jasper variant)
Silicon Dioxide (SiO2)
sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
mineral
Jasper
Silicon dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Tumbled Red Jasper
Quartz (Microcrystalline variety of chalcedony, SiO2)
mineral
Fossil Shark Tooth
Selachii fossil
fossil
Jasper
Microcrystalline quartz (SiO2)
sedimentary
Mammoth Tooth
Mammuthus tooth
fossil
Jasper
Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)
sedimentary
Jasper
Microcrystalline quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (Chalcedony), SiO2
sedimentary
Fossilized Tooth
Vertebrate Fossilized Tooth (Mineralized Biogenic Material)
fossil
Chert
Silicon dioxide (SiO2)
Sedimentary
Peridotite (Dunite/Peridot Xenolith)
Peridotite (predominantly Olivine (Mg, Fe)2SiO4)
igneous
Red glassy gemstone, possibly garnet
Unidentified red transparent material; garnet group (X₃Y₂(SiO₄)₃) is a possibility
gemstone
Fossil bivalve shell
Ribbed pectinid or related bivalve; originally calcite/aragonite (CaCO₃), likely partially mineralized
fossil
Sandstone
Sandstone (Siliciclastic Sedimentary Rock)
sedimentary
Likely rough blue-green beryl (aquamarine)
Beryl, Be₃Al₂Si₆O₁₈; blue-green color is caused mainly by iron
gemstone
Blue glassy mineral fragment, possibly dyed/cobalt-colored calcite or aragonite
Uncertain from image; vivid blue coloration may indicate treated calcite (CaCO₃), aragonite (CaCO₃), or synthetic glass
mineral
Likely weathered quartz-rich stone or fossil fragment
Indeterminate; possibly quartz-bearing sandstone, iron-stained quartz, or a fragmentary fossil
mineral
Tumbled yellow jasper or silicified rock fragment
Microcrystalline quartz (chalcedony), SiO₂, likely iron-oxide colored
mineral
Tumbled smoky quartz
Quartz, silicon dioxide (SiO₂), smoky variety
mineral
Likely rough quartz with iron-oxide staining
Quartz (SiO₂), possibly with iron-oxide inclusions or surface staining
mineral
Polished opal-bearing rock (likely boulder opal)
Opal, hydrated amorphous silica (SiO₂·nH₂O), in ironstone or host rock
gemstone
Smoky quartz
Quartz (SiO₂), likely smoky variety
mineral
Potassium feldspar
Orthoclase or microcline; KAlSi₃O₈
mineral
Tumbled serpentine
Serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile; commonly Mg₃Si₂O₅(OH)₄
metamorphic
Black tourmaline (likely schorl), polished
Schorl tourmaline — NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
mineral