Igneous, Metamorphic, And Sedimentary (Mixed Assemblage)

Weathered granite boulder

Granite, typically quartz–feldspar–mica assemblage

Weathered granite cobble

Granite, typically quartz–feldspar–mica assemblage

Mixed river-worn rock collection

Uncertain; likely quartzite, sandstone, basalt, and weathered granite or gneiss

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

Magnetite sand (black iron-oxide sand)

Magnetite, Fe₃O₄; commonly mixed with ilmenite and other heavy minerals

Mixed Gravel and Pebbles

Polylithic Alluvial Aggregate

Tumbled green jasper (probable serpentine-rich stone)

Jasper, microcrystalline quartz (SiO₂), possibly mixed with serpentine or chlorite

Blue Calcite

Calcium Carbonate (CaCO3)

Mixed rock and mineral specimens

Predominantly quartz-rich rocks, with a possible malachite-bearing specimen; exact identification is uncertain from the image

Crocodile Jasper

Microcrystalline Quartz (SiO2)

Smoky Quartz with Feldspar

SiO2 (Quartz) with KAlSi3O8 (Feldspar)

River Pebbles

Polymictic Gravel

Natural gemstone and mineral collection

Mixed specimens, including turquoise, tiger’s eye, amethyst, fluorite, pyrite, garnet, rose quartz, lapis lazuli, obsidian, rhodonite, red corundum, labradorite, calcite, lepidolite, sodalite, apatite, and others

Coarse sand with a small pebble

Unconsolidated siliciclastic sediment, chiefly quartz and rock fragments

Quartz

Silicon dioxide (SiO2)

Milky Quartz with Nephrite Jade

Silicon Dioxide (SiO2) with Ca2(Mg,Fe)5Si8O22(OH)2

Pyrite

Iron Sulfide, FeS2

Pyrite-bearing sulfide ore (likely pyrite with iron oxides)

Pyrite, FeS₂, possibly mixed with limonite/goethite and other sulfides

Dark gray weathered pebble, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Magnetite

Iron(II,III) oxide, Fe3O4

Likely quartz-rich metamorphic pebble

Possibly quartzite; exact identification is uncertain from the photo

Mixed small mineral specimens

Likely quartz varieties with possible rose quartz and iron-stained quartz; exact identification is uncertain from the blurred image

Pyrite

Iron Sulfide (FeS2)

Blue Apatite

Calcium phosphate fluoride/chloride, Ca5(PO4)3(F,Cl,OH)

Pyrite

Iron Sulfide (FeS2)

Lapis Lazuli

Lapis Lazuli (contains lazurite, calcite, pyrite)

Polished mixed rock, likely orbicular/epidote-bearing granite or basalt

Uncertain; probable quartz–feldspar–amphibole/epidote aggregate

Rounded river pebbles, likely basalt and sandstone/conglomerate

Probable basalt (dark specimen) and ferruginous sandstone or weathered conglomerate (tan specimen)

Mixed rounded fieldstones, likely granite and gneiss

Granite (quartz–feldspar–mica) and gneiss; exact identification is uncertain from the photograph

Clear Quartz

Silicon Dioxide (SiO2)

Rhodonite

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

Dark mafic rock, likely basalt

Basalt (fine-grained assemblage chiefly plagioclase and pyroxene, commonly with olivine and iron oxides)

Chakra Crystal Pendant

Mixed Quartz and Chalcedony (SiO2)

Crushed Granite and Quartz Gravel

Composite Igneous and Silicate Rock Aggregate

Rough Gemstone Grains (Mixed Sapphires and Quartz)

Corundum (Al2O3) and Quartz (SiO2)

Granite

Coarse-grained felsic intrusive igneous rock; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende

Iron-rich concretion or weathered limonite/goethite nodule

Limonite (hydrous iron oxides), commonly dominated by goethite (FeO(OH))

Banded iron formation (ironstone)

BIF; hematite–magnetite–quartz/chert assemblage

Granite Thin Section

Granitic rock (Phaneritic texture)

Fossiliferous limestone with silicified fossil material

Bioclastic limestone; likely marine mollusk/coral fragments, locally replaced by chalcedony or calcite

Mineral and Rock Collection (Assorted)

Mixed collection including Quartz (SiO2), Jasper (SiO2 with impurities), Rose Quartz, and Aventurine

Likely greenstone (metamorphosed mafic rock)

Greenstone; commonly chlorite–actinolite–epidote–albite assemblage