Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Chert (Yellow/Tan variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert Nodule (Flint)

Chert (Silicon Dioxide, SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Coquina

Biogenic Limestone (Coquina)

White Marble

Recrystallized Calcite (CaCO3)

Crushed Stone / Gravel

Aggregatus saxum (variable mineral composition)

Flint / Chert

Microcrystalline quartz (SiO2)

Mother of Pearl (Nacre) / Shell Fragment

Biogenic Calcium Carbonate (Aragonite and Conchiolin)

Diamond (as set in a metal alloy ring)

Diamond (Pure Carbon, C)

Fossilized Shell Impression / Siltstone Fossil

Bivalvia / Brachiopoda mold in Siltstone

Marble

Marble (metamorphosed limestone or dolostone), primarily composed of calcite (CaCO3) or dolomite (CaMg(CO3)2)

Sandstone

Arenite (composed primarily of Quartz: SiO2)

Chert (Black Chert or Flint)

Silicon Dioxide (SiO2)

Nephrite Jade

Nephrite

Slate

Metamorphic pelitic rock

Sandstone (Quartzose)

Sandstone (SiO2 dominated)

Tektite

Impactite (Natural Silicate Glass)

Chert (Yellow Jasper/Flint)

Microcrystalline Quartz (SiO2)

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (variations include Flint/Jasper)

Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert / Jasper

Silicon Dioxide (SiO₂)

Siltstone Pebble

Siltstone (composed of microscopic quartz and clay minerals)

Chert (Flint)

Chert (SiO2)

N/A - Man-made object (Jewelry Chain)

Antiqued or Oxidized Metal Chain (often Steel or Brass)

Sandstone

Sandstone (SiO2-rich clastic sedimentary rock)

Mother of Pearl (Nacre)

Calcium Carbonate (primarily aragonite, with conchiolin)

Sandstone or Limestone

Sedimentary Rock

Chert (often called Flint or Jasper if reddish)

Microcrystalline Quartz (SiO2)

Belemnoit (Fossil)

Belemnoidea (Order), Rostrum / Guard

Chert (Flint)

Silicon Dioxide (SiO2)

Fossilized Shark Tooth (Eroded)

Carcharodon sp. or Otodus sp. fragment (likely)

Brecciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Blue Goldstone

Synthetic glass with copper or cobalt/manganese inclusions

Chert (Green Chert or Jasper)

Microcrystalline Quartz (SiO2)

Chert (Flint/Chalcedony)

Silicon Dioxide (SiO2)

Chert Arrowhead

Chert (Cryptocrystalline variety of Quartz, SiO2)

Chert (and/or Flint)

Microcrystalline Quartz (SiO2)

Sandstone Pebble

Sandstone (primarily SiO2)

Chalk

Calcium Carbonate (CaCO3)

Chert (Flint)

Chert (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz