Sedimentary (Alluvial Deposit)

Mixed River Pebbles

Clastic Sedimentary Alluvial Deposit / Polymictic Conglomerate Clasts

River Rock (Quartz-dominated)

Silicon Dioxide (SiO2) mixture with varied clastic sediments

Citrine (or Yellow Chalcedony / Quartz)

Silicon Dioxide (SiO2)

Blue Zircon

Zircon (Zirconium Silicate, ZrSiO4)

Mixed stream gravel and cobbles

Polylithic alluvial deposit; individual clasts are not identifiable at this resolution

Yellow Quartz / Chalcedony

Silicon Dioxide (SiO2)

River Stone (River Pebbles)

Alluvial Deposit (typically Quartzite, Sandstone, or Granite clasts)

Rounded brown river pebble

Indeterminate lithic fragment; possibly weathered sandstone, mudstone, or basalt

Chalcedony (Agate/Carnelian variant)

Silicon Dioxide (SiO2)

Dendritic Jasper (Bumblebee like Agate)

Silicon Dioxide with inclusions (SiO2)

Brown Agate

Silicon Dioxide (SiO2)

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Yellow Chalcedony (Agate/Jasper mix)

Silicon Dioxide (SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Polished Mookaite Jasper

SiO2 (Silicon Dioxide with impurities)

Weathered river cobble, likely quartzite or sandstone

Indeterminate; probable quartz-rich sandstone/quartzite

Quartz (Citrine or Smoky variant)

Silicon Dioxide (SiO2)

Chert Pebble

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Yellow Chert (Microcrystalline Quartz)

Chert / SiO2 (Silicon Dioxide)

Chert (Yellow Jasper/Flint)

Microcrystalline Quartz (SiO2)

River Stone (Quartzite/Chert)

Metamorphosed Quartz-rich Sedimentary Rock

Chert (specifically Gray/Tan Chert Node)

Microcrystalline Quartz (SiO2)

Almandine Garnet (weathered)

Almandine (Fe3Al2(SiO4)3)

Chert Pebble

Microcrystalline or cryptocrystalline Quartz (SiO2)

Carnelian

Chalcedony (SiO2)

Yellow Jasper

SiO2 (Microcrystalline Quartz)

Amber

Fossilized Tree Resin

Jasper with Hematite inclusions

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3)

Quartz Pebble (with Dark Volcanic/Sedimentary Inclusion)

Silicon Dioxide (SiO2)

Quartz (with iron oxide staining)

Silicon Dioxide (SiO2)

Quartz (Citrine / Yellow Quartz)

Silicon Dioxide (SiO2)

Nephrite Jade

Ca2(Mg, Fe)5Si8O22(OH)2

Cassiterite in Iron-rich Matrix

Cassiterite (SnO2)

Gravel and Sediment Sample

Mixed clastic sediment

Basalt with Caliche Crust

Aphanitic Mafic Igneous Rock with Calcium Carbonate (CaCO3) coating

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Yellow Sapphire (Corundum)

Corundum (Aluminum Oxide, Al2O3)

Quartz Pebble

Silicon dioxide (SiO2)

Quartz (Milky or Smoky)

Silicon Dioxide (SiO2)

Quartzite Pebble

Quartzite (primarily SiO2)