Sedimentary (Microcrystalline Silicate)

White Marble

Recrystallized Calcite (CaCO3)

Jasper (Green Jasper/Chert)

Silicon Dioxide (SiO2)

Rhodonite

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

Rhodonite-bearing gneiss

Manganese-rich biotite gneiss with rhodonite (MnSiO₃)

Sandstone with Ironstone Concretion

Arenite with Ferruginous Cement

Sandstone (with ripple marks)

Arenite (SiO2 primarily)

Siltstone

Siltstone (primarily SiO2 with various silicates)

Serpentine (Serpentinite)

Serpentinite (complex silicate group including lizardite, chrysotile, and antigorite)

Chert Concretion (Flint)

Silicon Dioxide (SiO2)

Map Jasper (Picasso Stone)

Metamorphosed Calcium Carbonate (Crystalline Limestone or Marble with Silicate inclusions/impurities)

Sandstone (Fluvial Pebble)

Arenite

Sandstone (Ferruginous)

Arenite (with Iron Oxide)

Rounded river cobble

Likely quartz-rich sandstone or metamorphosed quartzite; exact identification is uncertain from the photograph

Polished river pebble

Indeterminate; likely fine-grained quartz-rich sedimentary rock or weathered volcanic rock

Marble

Recrystallized Calcite (CaCO3)

Marble

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

Likely limestone or chalky carbonate rock

Calcite-rich limestone; predominantly calcium carbonate (CaCO₃)

Weathered limestone or calcareous sandstone

Calcite-rich carbonate rock, predominantly CaCO₃; possibly fossiliferous limestone

Likely quartz-rich rock fragment

Indeterminate; probably microcrystalline quartz (SiO₂) with minor feldspar or weathering minerals

Polished orbicular jasper (likely ocean jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and other silicate inclusions

White Marble

Recrystallized Calcite Rock (CaCO3)

Green Calcite (often commercially called Green Onyx)

Calcium Carbonate (CaCO3)

Petrified Wood

Silicified Wood (SiO2)

Polished jasper or jasper-rich breccia

Microcrystalline quartz (SiO₂), commonly with iron oxides and other silicates

Polished ocean jasper (likely orbicular jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and other silicates

Petoskey Stone (Petrified Favosites)

Favosites (extinct colonial coral), CaCO3 with Silica replacement

Rhodonite

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

Weathered quartz-rich metamorphic rock

Likely quartzite or quartz-rich gneiss; exact identification requires a fresh surface and testing

Orbicular jasper

Siliceous microcrystalline quartz (chalcedony), commonly sold as ocean jasper

Fine-grained brown sand or weathered soil

Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains

Light-colored weathered stone, possibly limestone or quartz-rich rock

Indeterminate; likely calcitic limestone (mostly CaCO₃) or quartz sandstone (SiO₂)

Fossil-bearing limestone slab

Bioclastic limestone, likely containing brachiopod or bivalve impressions

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 inclusions)

Mica Schist with Biotite or Muscovite

Metamorphic rock rich in sheet silicates

Mica Schist with Garnet inclusions

Mica Schist (primarily Muscovite and Biotite - KAl2(AlSi3O10)(OH)2)

Mixed Mineral Assortment (Pyrite, Kyanite, Agate, Jasper)

FeS2 (Pyrite), Al2SiO5 (Kyanite), SiO2 (Agate/Jasper)

Weathered gray metamorphic rock, likely schist or slate

Foliated silicate rock; possibly mica schist or phyllite

Weathered limestone or calcareous concretion

Calcite-rich limestone; predominantly calcium carbonate (CaCO₃)

Pyritic Gneiss (with Garnet)

Gneiss containing Pyrite (FeS2) and Almandine Garnet (Fe3Al2(SiO4)3)

Polished gray stone, likely quartzite or river-worn granite

Tentatively quartzite (mostly microcrystalline SiO₂); exact identification is uncertain from the photograph

Picasso Stone

Metamorphosed Calcium Carbonate (Limestone)

Likely limestone or calcareous fossil fragment

Calcite-rich carbonate rock; possibly bioclastic limestone (CaCO₃)