Polished orange agate/jasper cabochon
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide coloration; exact variety uncertain
mineral
Category
Biogenic Material
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Polished green aventurine
Quartzite dominated by quartz (SiO₂), with green fuchsite mica or chlorite inclusions
mineral
Dark basalt or basaltic volcanic rock
Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar, pyroxene, and often olivine
igneous
Orbicular jasper (likely ocean jasper)
Silica-rich microcrystalline quartz/chalcedony with feldspar and accessory minerals; composition varies
mineral
Fossil coral (likely solitary rugose coral)
Rugosa; possibly genus Heliophyllum or similar
fossil
Rounded gray pebble
Indeterminate; likely a water-worn silicate or carbonate pebble
sedimentary
Tumbled pegmatitic granite
Granite, chiefly quartz–feldspar–mica; likely altered pegmatite
igneous
Tumbled sodalite (probable)
Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂
mineral
Dark mafic rock, likely basalt
Basalt; primarily plagioclase feldspar and pyroxene, commonly with olivine and iron oxides
igneous
Rose quartz
Quartz (silicon dioxide, SiO₂), pink variety
mineral
Iolite
Cordierite (Mg2Al3(AlSi5O18))
gemstone
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Sandstone
Quartzose Sandstone (Sedimentary Rock)
sedimentary
K-Feldspar (Potassium Feldspar)
Potassium Feldspar (Microcline or Orthoclase), KAlSi3O8
mineral
Septarian Nodule
Septarian Concretion (Calcite, Aragonite, Limestone)
sedimentary
Green Quartzite
Metamorphic Quartzite (often colored by chromium-bearing minerals or fuchsite)
metamorphic
Graphic Granite
Pegmatitic Granite
igneous
Sandstone
Sedimentary Rock (Quartz arenite/Arkose)
sedimentary
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Sandstone
Quartz Arenite / Clastic Sedimentary Rock
sedimentary
Sandstone
Sedimentary Rock (Quartz Arenite)
sedimentary
Quartzite Pebble
Metamorphic Quartzite (SiO2)
metamorphic
Sandstone
Quartz Arenite / Sedimentary Rock
sedimentary
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Dumortierite Quartz
Dumortierite in Quartz (Al6O3(BO3)(SiO4)3)
mineral
Yellow Jasper with Red Inclusion
Silicon Dioxide (SiO2) with Iron Oxides
sedimentary
Amazonite in Quartz
K(AlSi3O8) - Potassium Feldspar with Quartz (SiO2)
mineral
River Pebble (Greywacke / Basalt Pebble)
Indeterminate Rounded Pebble (composed of quartz, feldspar, or mafic minerals)
sedimentary
Red Tuff / Sandstone
Rhyolitic Tuff / Pyroclastic Volcanic Rock
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Chalcedony Pebble with Jasper/Iron Oxide Cortex
Silicon Dioxide (SiO2)
mineral
Quartz with Iron Staining
Silicon Dioxide (SiO2) with Hematite/Limonite inclusions
mineral
Sandstone (Quartzose)
Sandstone (SiO2 dominated)
sedimentary
Quartz Pebble (Iron-stained Chalcedony / Chert)
Silicon Dioxide (SiO2)
sedimentary
Sandstone (Pebble)
Sandstone (SiO2 dominated with minor feldspar/clay)
sedimentary
Unakite
Altered Granite (Unakite)
metamorphic
Sandstone (with Iron Staining)
Quartz Arenite / Ferruginous Sandstone
sedimentary
Unakite
Altered Granite (Epidotized Granite)
metamorphic
Epidote (Unakite component) / Green Quartzite
Ca2(Al,Fe)3(SiO4)3(OH)
metamorphic
Gneiss
Gneiss (Foliated Metamorphic Rock)
metamorphic
Sandstone Pebble
Quartz Arenite / Sandstone
sedimentary
Porphyry
Porphyritic Igneous Rock
igneous