Sedimentary Rock (Altered)

Tumbled river pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; exact identification requires testing

Likely garnet-bearing schist

Mica schist, possibly containing almandine garnet (Fe₃Al₂(SiO₄)₃)

Unidentified greenish-gray rock fragment

Tentatively altered basalt or basaltic volcanic rock; mineral identification requires testing

Polished tiger iron

Tiger iron; quartz (SiO₂) with hematite/magnetite and crocidolite-derived riebeckite/goethite

Weathered sandstone or altered volcanic rock

Indeterminate; likely quartz–feldspar-rich sandstone, possibly tuff

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium), CuAl6(PO4)4(OH)8·4H2O

Likely shale or slate

Fine-grained, clay-rich rock; possibly slate (low-grade metamorphosed shale). Exact identification is uncertain from the photo.

Polished jasper

Microcrystalline quartz (SiO₂), likely brecciated or orbicular jasper

Likely weathered brown rock fragment

Indeterminate; possibly iron-oxide-stained sandstone or laterite

Rounded dark river pebble, possibly serpentinite

Serpentinite (serpentine-group minerals; commonly lizardite/chrysotile/antigorite), identification tentative

Greenstone or Epidote-rich rock

Epidote or Chlorite schist/greenstone

Greenstone pebble

Greenschist-facies mafic rock, commonly derived from basalt; likely rich in chlorite, actinolite, and epidote

Peridotite

Ultramafic igneous rock (primarily olivine and pyroxene)

Likely weathered sandstone or metasandstone

Quartz-rich sandstone (possibly weakly metamorphosed metasandstone)

Weathered granitic or feldspathic pebble

Likely granite/granodiorite; quartz–feldspar–mica aggregate

Weathered greenstone

Metamorphosed mafic rock, commonly chlorite–actinolite schist or altered basalt

Rounded river pebble, likely altered limestone or sandstone

Probable micritic limestone (calcite-rich, CaCO₃) or fine-grained sandstone

Rounded dark pebble, likely basaltic andesite

Fine-grained mafic volcanic rock; probable basalt or andesite, identification uncertain from image alone

Vesicular basalt (possibly slag-contaminated)

Basalt; chiefly plagioclase and pyroxene, with possible olivine and secondary minerals

Small shell fragment (likely gastropod or bivalve fossil)

Fossilized calcium-carbonate shell; chiefly aragonite or calcite (CaCO₃)

Pink-and-green mineral specimen, possibly unakite

Unakite, an epidote–feldspar–quartz rock; identification is uncertain from the photo

Limestone with Weathering Rind

Calcium Carbonate (CaCO3) - Bioclastic or Micritic Limestone

Ironstone / limonite-rich rock

Limonite, chiefly hydrated iron oxides (FeO(OH)·nH₂O), commonly mixed with goethite and hematite

Rounded river pebble, likely sandstone or weathered quartz-rich sedimentary rock

Indeterminate siliciclastic pebble; likely quartz–feldspar sandstone, with possible iron-oxide staining

Iron-rich brown stone, possibly weathered chert or ironstone

Undetermined; likely iron-oxide-bearing silica-rich rock (chert/ironstone)

Tumbled polymictic stone, likely jasper-bearing conglomerate

Siliciclastic conglomerate with microcrystalline quartz (jasper/chert) and altered volcanic or feldspathic clasts

Weathered volcanic rock, likely andesite or basaltic-andesite

Fine-grained plagioclase–pyroxene volcanic rock; possible altered andesite (exact identification requires testing)

Peridotite

Ultramafic igneous rock

Weathered porphyritic volcanic rock

Likely altered andesite or rhyolite porphyry

Weathered metamorphic rock, likely chlorite schist or greenstone

Chlorite-rich schist/greenschist; exact identification requires testing

Polished greenstone pebble

Likely chlorite- or actinolite-bearing greenstone (metamorphosed mafic rock)

Unakite

Epidotized Granite

Likely weathered copper-bearing rock

Indeterminate from the photo; possibly malachite-bearing rock (Cu₂CO₃(OH)₂)

Greenstone (likely altered basalt)

Metamorphosed mafic volcanic rock, commonly chlorite- and actinolite-rich; exact identification requires testing

Likely greenstone (metamorphosed mafic rock)

Greenstone; commonly metamorphosed basalt or dolerite, with chlorite, actinolite, epidote, and albite

Epidote

Epidote (Ca2(Al,Fe)3(SiO4)3(OH))

Weathered granite fragment

Granite, chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende

Dumortierite Quartz

Dumortierite-bearing Quartz (SiO2 with Al7BO3(SiO4)3O3)

Weathered sandstone (probable)

Quartz-rich sandstone, largely composed of cemented quartz grains (SiO₂)

Weathered volcanic rock, likely basalt

Basalt; primarily plagioclase feldspar, pyroxene, and often olivine

Turquoise

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

Weathered quartz-rich sandstone

Quartz arenite (likely feldspathic sandstone)