Seashell Fragment
Calcium carbonate (CaCO3) - primarily Aragonite or Calcite
fossil
Category
Antropogenic (Man Made Material)
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Granite, possibly granodiorite
Coarse-grained felsic plutonic rock; chiefly quartz (SiO₂), potassium feldspar and plagioclase feldspar, with biotite and/or hornblende
igneous
Diamond (Cut Gemstone)
Carbon (C)
gemstone
Marble
Marble (metamorphosed limestone or dolostone), primarily composed of calcite (CaCO3) or dolomite (CaMg(CO3)2)
metamorphic
Brecciated jasper (likely red-and-cream jasper)
Jasper, an opaque microcrystalline variety of quartz; primarily cryptocrystalline SiO₂ with iron-oxide staining and possible chalcedony/quartz veining
gemstone
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
igneous
Sea Glass (Cobalt Blue)
Amorphous Silica (Glass with Cobalt additives)
Anthropogenic specimen (man-made)
Granodiorite
Phaneritic Plutonic Intermediate-Felsic Rock
igneous
Diamond
Carbon (C)
mineral
Quartz
Silicon dioxide (SiO₂)
Mineral
Sandstone Concretion
Sedimentary concretion
Sedimentary
Blue Lace Agate
Chalcedony (SiO2) with trace inclusions
mineral
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Sandstone (Water-worn Cobble)
Arenite (SiO2 with CaCO3 or Fe2O3 cement)
sedimentary
Turquoise
Hydrous phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
gemstone
Blue Sea Glass
Amorphous Silica (Anthropogenic glass)
not a rock (man-made origin)
Fossilized echinoid (sea urchin), likely a flint/chalk-associated test
Echinoid fossil; likely a regular echinoid such as Echinocidaris or related taxon, composed mainly of recrystallized calcite (CaCO₃)
fossil
Diabase (Dolerite)
Diabase / Dolerite
igneous
Land Snail Shell
Gastropoda (Calcium Carbonate, CaCO3)
fossil
Goldstone (aventurine glass)
Synthetic copper-bearing soda-lime glass; commonly sold as red goldstone
gemstone
Pearl
Biogenic CaCO3 (Aragonite and Calcite)
mineral
Chert (Flint / Quartz Nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Flint
SiO2 (Cryptocrystalline Quartz)
sedimentary
Pearl (Biogenic Mineraloid)
Calcium carbonate (CaCO3) primarily as Aragonite
mineral
Gypsum (Satin Spar / Alabaster variety)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
mineral
Granite
Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)
igneous
Lava Rock (Dyed)
Basalt / Volcanic scoria
igneous
Chert Arrowhead
Cryptocrystalline Quartz (SiO2)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
sedimentary
Siltstone Pebble
Siltstone (composed of microscopic quartz and clay minerals)
sedimentary
Chert Pebble/Nodule
Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)
Sedimentary
Beaded Jewelry (Assorted Gemstones)
Various minerals, including but not limited to Quartz (SiO2), Garnet (X3Y2(SiO4)3), Jade (Na(Al,Fe)Si2O6), Amethyst (SiO2),等の多様な組み合わせ
Mineral, Jewelry
Tumbled sodalite with white calcite veining
Sodalite, Na8(Al6Si6O24)Cl2, commonly intergrown with calcite, CaCO3
mineral
Chert Arrowhead
Microcrystalline Quartz (SiO2)
sedimentary
Diamond (or Cubic Zirconia)
Carbon (C) or Zirconium Dioxide (ZrO2)
gemstone
Vesicular Basalt (or Scoria)
Vesicular Basalt
igneous
Synthetic Costume Accessory (Non-Geological)
Polyester and Acrylic Fiber (Anthropogenic polymer)
Synthetic / Man-made textile
Gold (Elemental Metal)
Gold (Au)
Mineral
Chalk
CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock
Sedimentary
Belemnoit (Fossil)
Belemnoidea (Order), Rostrum / Guard
sedimentary
Granite
Phaneritic Plutonic Felsic Rock
igneous
Granite
Granite (Phaneritic igneous rock)
igneous