Bored Siltstone (Holey Rock)
Siltstone with Pholad borings (Lithophaga/Pholadidae trace fossils)
sedimentary
Category
Not A Geological Specimen
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Asphalt (Bituminous Pavement Bit)
Bitumen-bound aggregate (Petrochemical-bound composite)
sedimentary (anthropogenic/technogenic)
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
mineral
Blue Calcite
Calcium Carbonate (CaCO3)
mineral
Red Quartzite / Ferruginous Sandstone
Quartzite (SiO2 with iron oxide impurities)
metamorphic
Olivine in Basalt (Peridotite Xenolith)
Forsterite-rich Olivine (Mg2SiO4) in Aphanitic Basalt
igneous
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
mineral
Epidote in Granite Gneiss
Epidote bearing Orthogneiss (Ca2(Al,Fe)3(SiO4)3(OH))
metamorphic
Yellow Quartz (Citrine or Iron-Stained Quartz)
Silicon Dioxide (SiO2)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt
igneous
Rose Quartz
Silicon Dioxide with traces of titanium, iron, or manganese (SiO2)
mineral
Chalcedony (Agate/Chert variety)
Silicon Dioxide (SiO2)
mineral
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2) with Hematite/Limonite
mineral
Snowflake Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Fluorite Tower
Fluorite (Calcium Fluoride - CaF2)
mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Quartz (Crystal Cluster)
Silicon Dioxide (SiO2)
mineral
Banded Agate (Tumbled)
Silicon Dioxide (SiO2) - variety of Chalcedony
mineral
Diamond
Native Carbon (C)
mineral
Clear Quartz Crystal (Herkimer Diamond style)
Silicon Dioxide (SiO2)
mineral
Collection of Minerals and Ores
Various (e.g., Uraninite (U3O8), Carbon (C), Native Gold (Au), Hematite (Fe2O3), Galena (PbS), etc.)
mineral
Smoky Quartz
Smoky Quartz (SiO ₂)
Mineral
Sunstone (Feldspar variety)
Oligoclase or Andesine (Na,Ca)(Al,Si)4O8
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Carnelian (a variety of Chalcedony)
SiO2 (Silicon Dioxide) primarily colored by iron oxide (Hematite)
mineral
Epidosite (Epidote-Quartz rock)
Epidote-rich hydrothermal rock
metamorphic
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
man-made alloy (metallic)
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Sandstone (Weathered)
Arenite (primarily SiO2)
sedimentary
Quartz (Milky/Chalcedony variety)
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Sandstone (likely Calcareous or Quartz-rich)
Arenite (SiO2 based typically)
sedimentary
Chalcedony (Agate/Carnelian precursor)
Chalcedony (Silicon Dioxide, SiO2)
mineral
Chert with Crinoid Fossil Impression
Microcrystalline Quartz (SiO2) with Crinoidea fossil impression
sedimentary
Quartz (Milky or Rough Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz (Milky/Yellowish variety)
Silicon Dioxide (SiO2)
mineral
Quartzite (Iron-stained)
Quartzite (SiO2)
metamorphic
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Ferruginous Quartz
Quartz (Silicon Dioxide, SiO2) with iron oxide inclusions
mineral
Rose Quartz
Crystalline Silicon Dioxide with trace Titanium/Manganese/Iron (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Gold Nugget
Native Gold (Au)
mineral