Not A Natural Rock (Man Made Composite)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Moonstone

Orthoclase Feldspar (KAlSi3O8) or Albite mixtures

Banded Gneiss

Gneiss (Metamorphic high-grade rock)

Greenschist / Greenstone

Greenschist facies metabasite

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Porphyritic Basalt (Flowerstone)

Porphyritic Basalt (Mafic volcanic rock)

Dolomite

Dolomite (CaMg(CO3)2)

Lapis Lazuli

Lapis Lazuli (a rock composed primarily of Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2, with varying amounts of Calcite, Pyrite, and Sodalite).

Peridot

Olivine (Magnesium Iron Silicate), (Mg, Fe)2SiO4

Chert Nodule (River Cobble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded Calcite (often commercially sold as 'Mexican Onyx' or 'Honey Onyx')

Calcite (Calcium Carbonate, CaCO3)

Caliche (also known as hardpan, calcrete, kankar)

Primarily composed of calcium carbonate (CaCO₃), often mixed with other minerals like quartz, clay minerals, and iron oxides.

Quartz

Quartz (SiO2)

Magnetite / Hematite mix (Iron Ore)

Fe3O4 (Magnetite) / Fe2O3 (Hematite)

River Quartzite (Water-worn Quartzite)

Quartzite (primarily SiO2)

Quartz Druzy Geode

Silicon Dioxide (SiO2) - Crystalline Variety

Quartzite

Quartzite (primarily SiO2)

Moonstone

Orthoclase Feldspar (containing Albite lamellae), (KAlSi3O8)

Rhodonite

Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3

Quartzite

Quartzite (SiO2)

Sand Dollar Fossil (Echinoidea)

Class Echinoidea (likely order Clypeasteroida), CaCO3 (Calcite)

Gold

Native Gold (Au)

Quartz (likely) / Siliceous rock with quartz phenocrysts (if a rock fragment)

Quartz (SiO₂)

Chert (Nodule)

Microcrystalline Quartz (SiO2)

Bauxite

Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))

Leopard Skin Jasper

Chalcedony (cryptocrystalline Quartz)

Quartzite

Quartzite (Primary mineral: Quartz, SiO2)

Yellow Quartzite Pebble

Quartzite (primarily Silicon Dioxide - SiO2)

Sandstone

Arenite (primarily Quartz, SiO2)

White Topaz

Topaz - Al2SiO4(F,OH)2

Ruby and Diamond in Gold Setting

Corundum (Al2O3) and Diamond (C)

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Snowflake Obsidian

Spherulitic Volcanic Glass (SiO2 + impurities)

Bi-Color Tourmaline (or Watermelon Tourmaline)

Tourmaline (complex borosilicate mineral group with general formula AD3G6(BO3)3T6O18(OH,O)4)

Moonstone

Orthoclase (Potassium aluminum silicate - KAlSi3O8)

Sandstone

Arenite (composed primarily of SiO2)

Quartz (likely Yellow/Orange variety, possibly Citrine or Chalcedony with iron staining)

Quartz (SiO₂)

Magnetite

Magnetite (Fe3O4)

Hematite

Hematite (Fe2O3)

General Gravel (River Rock/River Stones)

Mixed Lithic Sediments (Conglomerate Clasts)