Mineral (Silicate Replaced Organic Material)

Dark gray flint or chert fragment

Microcrystalline quartz (SiO₂), commonly with minor chalcedony and impurities

Tumbled jasper (likely brecciated or ocean jasper)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide inclusions

Chert (Flint)

Microcrystalline Quartz (SiO2)

Fossil shell impression or shell-bearing limestone

Indeterminate bioclastic carbonate; likely mollusk fragment preserved in limestone or mudstone

Blue glass-like gemstone specimen (likely dyed or synthetic quartz)

Uncertain; possibly blue-dyed quartz or synthetic glass, not confidently identifiable from the image

Sandstone

Arenite

Weathered quartz-rich pebble, possibly granitic gneiss

Quartz–feldspar–mica aggregate; likely granitoid or gneiss

Jasper

Silicon dioxide (SiO2) with impurities

Petrified Wood

Silicified Wood (SiO2)

Graphite

Graphite (Carbon, C)

Tiger's Eye (Jasper-like Chalcedony)

Silicon dioxide (SiO2) - Pseudomorph after Crocidolite

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Likely tumbled brown jasper or iron-rich chert

Microcrystalline quartz (SiO₂), probably colored by iron oxides

Pyrite (Pseudomorph)

Iron Sulfide (FeS2)

Plume Agate

Silicon Dioxide (SiO2) - Chalcedony Variety

Blue Topaz

Al2SiO4(F,OH)2

Chert (often called Flint or Jasper locally)

Chert (Microcrystalline Quartz, Formula: SiO2)

Green Calcite (often commercially called Green Onyx)

Calcium Carbonate (CaCO3)

Flint or chert, possibly a knapped stone tool

Microcrystalline quartz (SiO₂), commonly chalcedony with possible carbonaceous impurities

Tumbled orange chalcedony / jasper

Microcrystalline quartz, SiO₂, likely iron-stained chalcedony or quartz-rich jasper

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), likely jasper/chert

Fossilized Bone

Fossilized Vertebrate Bone (Per mineralized)

Tumbled yellow-brown quartz/chert fragment

Microcrystalline quartz (SiO₂), possibly jasper or chalcedony

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), possibly iron-bearing jasper

Weathered sandstone or limestone fragment

Likely quartz-rich sandstone or micritic limestone; exact identification requires testing

Trilobite fossil

Fossilized trilobite; exact genus/species indeterminate

Sandstone (with Moss)

Quartz Arenite / Sandstone

Polished black-and-gold pebble, likely jasper or iron-rich chert

Microcrystalline quartz (SiO₂), probably jasper/chert with iron-oxide bands

Fossilized Rugose Coral (Horn Coral)

Order Rugosa

Slag (Industrial Byproduct)

Artificial silicate/iron byproduct

Amygdaloidal Basalt with Epidote

Amygdaloidal Basalt (Mafic volcanic rock)

Petrified Wood

Silicified Wood (SiO2)

Fossilized Horse Tooth

Equus sp. (Tooth)

Black Kyanite

Aluminum Silicate (Al2SiO5)

Petrified Wood

Silicified Wood

Tumbled dark brown stone, likely jasper or iron-rich chert

Microcrystalline quartz (SiO₂), possibly iron-oxide-bearing jasper/chert

Jasper

Microcrystalline quartz (SiO2)

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets

Weathered jasper pebble (probable red jasper/chert)

Microcrystalline quartz, SiO₂, colored mainly by iron oxides

Pyrite (Fool's Gold) Cube

Iron Sulfide (FeS2)

Jasper

Silicon dioxide (SiO2)

Chert / Flint

Microcrystalline or cryptocrystalline quartz (SiO2)