Sedimentary (Man Made Composite)

Chert (vuggy/nodular)

Microcrystalline Quartz (SiO2)

Red Jasper

Silicon dioxide (SiO2) with iron oxide inclusions

Howlite

Howlite (Calcium borosilicate hydroxide, Ca2B5SiO9(OH)5)

Marble

Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)

Celestine (Celestite)

Strontium sulfate (SrSO4)

Hematite

Iron(III) oxide (Fe2O3)

Chert (specifically Flint or Jasper variant)

Microcrystalline Quartz (SiO2)

Gold

Native Gold (Au)

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Chert (often called Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jasper with Quartz inclusion

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Jasper (brecciated or orbicular variety)

Silicon dioxide (SiO2) with iron oxide inclusions

Grey Slate

Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)

Dalmatian Stone

Peralkaline Feldsphathic Igneous Rock

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Agate (specifically Moss or Plume Agate nodding toward Agatized Wood)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz (Chalcedony)

Banded Agate (River Stone)

Agate (Silicon Dioxide - SiO2)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Vuggy Quartz on Matrix

Silicon Dioxide (SiO2)

Honey Calcite Geode Segment

Calcite (Calcium Carbonate, CaCO3)

Limonite (with Goethite/Ironstone)

FeO(OH)·nH2O (Hydrated Iron Oxide)

Slate with Red Sandstone Landscaping Rock

Foliated Pelitic Metamorphic Rock (Slate) and Ferruginous Sandstone

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Quartz (Druzy Quartz)

Silicon Dioxide (SiO2)

Yellow Quartzite River Cobble

Meta-quartzite (SiO2 with iron oxide staining)

Granite (Dioritic or Hornblende-rich)

Phaneritic Plutonic Felsic to Intermediate Igneous Rock

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Orange Quartzite (River Pebble)

Quartzite (primarily SiO2)

Yellow Quartz Pebble (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Fossilized Sea Urchin (Echinoid)

Echinoidea (Class); commonly Clypeasteroida for sand dollar types

Limonite (often after Hematite or Goethite)

Limonite (FeO(OH)·nH2O)

Druzy Quartz on Host Rock

Silicon Dioxide (SiO2)

Black Opal

Hydrated Silica (SiO2·nH2O)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated Iron Oxide)

Petrified Wood

Silicified Wood (primarily SiO2)

Jasper and Chert Conglomerate

Ferruginous Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Jasper

Jasper (Silicon Dioxide, SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Gneiss (with Quartz and Mica)

Gneiss

Rough Agate/Chert Nodules

Cryptocrystalline Quartz (SiO2)