Greenstone (likely serpentinite or greenstone pebble)
Serpentinite-rich ultramafic rock; commonly dominated by serpentine-group minerals, with possible chlorite, actinolite, or magnetite
metamorphic
Category
Mineral (Synthetic Paper And Ink Polymorph)
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Tumbled jasper, likely picture jasper or brecciated jasper
Microcrystalline quartz (SiO₂), chiefly chalcedony with iron-oxide pigments
mineral
Likely weathered quartz-rich rock fragment
Uncertain; possibly granitic pegmatite or quartz-bearing metamorphic rock
igneous
Weathered quartz-rich pebble (likely milky quartz or quartzite)
Quartz, silicon dioxide (SiO₂); possibly quartzite, a metamorphic quartz rock
mineral
Weathered granitic rock fragment
Granite, predominantly quartz–feldspar–mica assemblage
igneous
Tumbled dark stone, likely basalt or basaltic rock
Fine-grained mafic volcanic rock; commonly basalt, composed chiefly of plagioclase and pyroxene with possible olivine and iron oxides
igneous
Milky quartz pebble
Quartz (silicon dioxide, SiO₂)
mineral
Milky quartz (likely weathered quartzite or quartz vein fragment)
Quartz, silicon dioxide (SiO₂)
mineral
Biotite-rich gneiss (probable)
Foliated quartz–feldspar–biotite gneiss; composition commonly includes quartz (SiO₂), feldspar, and biotite mica
metamorphic
Black basalt fragment
Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine
igneous
Vesicular basalt (likely weathered volcanic rock)
Basalt, commonly composed of plagioclase, pyroxene, and olivine
igneous
Dark fine-grained river pebble, likely basalt or diabase
Basaltic rock; chiefly plagioclase feldspar and pyroxene, with possible magnetite
igneous
Quartz Vein in Metamorphic Rock
Quartz-veined Schist or Gneiss
metamorphic
Quartz Sand
Silicon Dioxide (SiO2)
sedimentary
Wulfenite
Lead Molybdate, PbMoO4
mineral
Olivine
(Mg,Fe)2SiO4
mineral
Quartz Vein in Greenstone
Metamorphic rock with quartz vein (SiO2 / mixed silicates)
metamorphic
Quartz (Tumbled)
Silicon Dioxide (SiO2)
mineral
Blue Apatite
Fluorapatite / Chlorapatite / Hydroxylapatite (Ca5(PO4)3(F,Cl,OH))
mineral
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Basalt Pebble with Vesicles
Vesicular Basalt
igneous
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Chert (or Limestone)
Sedimentary Cryptocrystalline Quartz (SiO2) or Calcium Carbonate (CaCO3)
sedimentary
African Turquoise (Jasper)
Impure variety of silica, primarily Quartz (SiO2) with various inclusions
sedimentary
Lava Rock (Basaltic Scoria)
Vesicular Basalt
igneous
Chert
Chert (SiO2)
sedimentary
Fluorite
Calcium Fluoride (CaF2)
mineral
Pink Thulite (in Pumice-like texture)
Pink Zoisite (Mn-bearing Zoisite), Ca2Al3(SiO4)3(OH)
metamorphic
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Jadeite
NaAlSi2O6; Jadeite silicate mineral
metamorphic
Hematite (Tumbled)
Iron(III) oxide (Fe2O3)
mineral
Calcite on Host Rock
Calcium Carbonate (CaCO3)
mineral
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
mineraloid
Chert / Flint
Chert (SiO2)
sedimentary
Jadeite (Nephrite-Jadeite blend)
Jadeite (NaAlSi2O6)
metamorphic
Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
igneous
River Rock (Greywacke/Sandstone)
Lithic Wacke
sedimentary
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Quartz (Milky/Clear)
Silicon Dioxide (SiO2)
mineral