Sedimentary (Secondary Classification For A Weathered Mineral Specimen)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate quartz–feldspar aggregate; likely weathered granite (quartz, feldspar, minor iron oxides)

Quartz geode

Microcrystalline and crystalline quartz, SiO₂, likely with chalcedony and iron-oxide staining

Red-and-white porphyritic granite fragment

Granite, likely alkali-feldspar granite; quartz + feldspar with minor mafic minerals

Limonite

FeO(OH)·nH2O (Hydrated iron oxide)

Unidentified Rock Fragment

Unknown

Likely iron meteorite fragment

Iron–nickel meteorite, primarily kamacite and taenite (Fe–Ni alloy)

Limonite with Trace Fossils

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Iron-rich meteorite candidate

Possibly an iron meteorite or stony-iron meteorite; exact identification requires testing

Agate Pebble (Desert Agate / Chalcedony Nodule)

Silicon Dioxide (SiO2)

Turquoise

Hydrated phosphate of copper and aluminum - CuAl6(PO4)4(OH)8·4H2O

Fossiliferous limestone

Bioclastic carbonate rock, chiefly calcite (CaCO₃), with fossil shells/coral fragments

Iron-rich chondritic meteorite candidate

Unclassified stony meteorite; possible ordinary chondrite (H/L type)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)

Weathered vesicular volcanic rock, likely pumiceous andesite or rhyolite

Pumiceous intermediate-to-felsic volcanic rock; commonly composed of plagioclase, quartz, alkali feldspar, and volcanic glass, with possible iron-oxide staining

Polished orbicular granite (likely larvikite-type stone)

Coarse-grained granitoid composed mainly of feldspar, quartz, and dark mafic minerals; exact variety is uncertain from the image

Agate

Silicon Dioxide (SiO2)

Limonite (with Pyrite)

Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O

Limonite

Limonite (Hydrous iron oxides, predominantly Goethite FeO(OH)·nH2O)

Petrified wood

Silicified wood; commonly quartz/chalcedony (SiO₂) replacing organic tissue

Yellow-green serpentine (likely)

Serpentine-group phyllosilicate, commonly lizardite or antigorite; approximate formula Mg₃Si₂O₅(OH)₄

Weathered rounded pebble

Likely altered granite or granitic gneiss fragment; exact identification is uncertain from the image

Milky quartz-rich rock, likely quartzite or quartz vein material

Quartz (SiO₂), probably intergrown with feldspar and weathered mica/clay minerals

Vesicular basalt (possible scoria)

Basaltic volcanic rock; chiefly plagioclase, pyroxene, and iron-rich minerals, with vesicles formed by trapped gas

Limonitic Iron Ore / Goethite

Hydrated Iron(III) oxide-hydroxide (primarily FeO(OH)·nH2O)

Weathered granite pebble

Granite; primarily quartz, feldspar, and mica

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Limonite

FeO(OH)•nH2O

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O

Possible iron-rich meteorite

Uncertain; likely an ordinary chondrite (stony meteorite), pending testing

Iron Ore (Limonite and Hematite)

Goethite/Limonite (FeO(OH)·nH2O) and Hematite (Fe2O3)

Weathered river cobble, possibly sandstone or volcanic tuff

Indeterminate lithology; likely fine-grained sandstone/siltstone, with possible iron-oxide veining

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Chert (specifically Agate/Jasper variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Rhodochrosite

Manganese Carbonate (MnCO3)

Kaolinite (China Clay)

Kaolinite (Al2Si2O5(OH)4)

Limonite (Iron Ore)

Limonite (Hydrous iron(III) oxide-hydroxide mixture, FeO(OH)·nH2O)

Sandstone with Quartz Veining

Arenite with SiO2 veins

Limonite

FeO(OH)·nH2O

Weathered iron-rich rock, possibly laterite or limonite-bearing stone

Hydrated iron oxides/hydroxides, chiefly limonite-goethite mixture; exact identification requires testing

Feldspar-rich igneous rock, likely granite or gneiss fragment

Granite-like quartz–feldspar rock; exact identification is uncertain from the blurred image

Chert (River Pebble)

Microcrystalline Quartz (SiO2)