Sedimentary And Metamorphic

Anthracite Coal

Anthracite (Carbon-based sedimentary-derived metamorphic rock)

K2 Stone

Azurite in Granite

Pyrite in a host rock

Pyrite (FeS₂), embedded in a likely sedimentary or metamorphic matrix

Variscite

AlPO4·2H2O

Weathered fine-grained stone, likely sandstone or quartzite

Quartz-rich sandstone (possibly weakly metamorphosed quartzite); predominantly SiO₂

River Pebbles and Quartz

Mixed Igneous, Sedimentary, and Metamorphic Rocks (Silicon Dioxide SiO2 dominant)

Rounded gray stone, likely slate or fine-grained sandstone

Probable slate (low-grade metamorphosed shale) or lithic sandstone; exact identification requires testing

Milky quartz with iron staining

Quartz, silicon dioxide (SiO₂)

Weathered quartz-bearing rock, possibly calcite vein fragment

Indeterminate; likely quartz (SiO₂) with carbonate minerals such as calcite (CaCO₃)

Weathered limestone or marble slab

Likely calcite-rich carbonate stone; exact identification is uncertain from the image

Iron-stained quartz

Quartz (SiO₂), colored by iron-oxide/hydroxide staining

Milky quartz

Quartz (SiO₂), likely massive to small-crystalline variety

Milky Quartz with Iron Inclusions

Quartz (Silicon Dioxide, SiO2)

Iron-stained milky quartz

Quartz (SiO₂), with reddish-brown iron-oxide staining

Weathered quartz-rich rock fragment

Likely milky quartz–bearing quartzite or silica-rich chert; exact identification requires testing

Small white mineral fragment

Likely quartz (SiO₂), possibly calcite (CaCO₃)

Quartz-rich limestone or calcitic marble

Calcite (CaCO₃), possibly with quartz (SiO₂)

Polished operculum (“Shiva eye” shell)

Calcium-carbonate shell operculum, commonly from a turban snail (family Turbinidae); not a mineral specimen

Possible shale or slate fragment

Fine-grained clay-rich rock; possibly slate (low-grade metamorphosed shale)

Green Jasper

Silicon Dioxide (SiO2) with iron silicate inclusions

Orange Calcite (likely polished specimen)

Calcite

Calcite

Calcite (CaCO3)

Amethyst and mixed gemstone bracelet

Amethyst: purple quartz, silicon dioxide (SiO₂); likely accompanied by other quartz or decorative mineral beads

Pyrite-bearing rock (likely pyrite schist or pyritized shale)

Pyrite (FeS₂) in a fine-grained schistose or shale matrix

Likely quartz-rich rock with white quartz veins or patches

Quartz-bearing rock; exact rock type cannot be determined from the photograph

Likely quartz-rich pebble fragment

Quartz (SiO₂), possibly milky quartz or quartzite; the photo is insufficient to distinguish them confidently

Rock and Mineral Collection

Mixed Geological Specimens

Oyster shell fragment

Ostreidae shell; primarily calcite (CaCO₃)

Tiger's Eye

Quartz pseudomorph after crocidolite (SiO2)

Brown quartz-rich pebble (likely chert or weathered quartzite)

Quartz (SiO₂), possibly microcrystalline quartz/chert or quartzite

Green chalcedony (possibly chrysoprase) cabochon

Chalcedony, microcrystalline quartz (SiO₂); chrysoprase is nickel-colored chalcedony

Mixed Tumbled Gemstones

Various silicate and oxide minerals

Mixed Tumbled Gemstones and Minerals

Various silicate and oxide minerals

Limonite pseudomorph after pyrite

Goethite / Limonite pseudomorph after Pyrite (Fe3+O(OH) replacing FeS2)

Jasper Conglomerate (Puddingstone)

Siliceous Conglomerate (Quartz and Jasper clasts in a fine-grained matrix)

Weathered sandstone or iron-stained quartzite

Quartz-rich sandstone; possibly weakly metamorphosed quartzite (SiO₂ with iron-oxide coatings)

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Polished Stone Pendant (Identity Unclear)

Unknown (Possibly Jasper/Agate/Quartz mixture)

Gemstone Beads

Various mineral species

Jasper

SiO2

Clear Quartz

Silicon Dioxide (SiO2)

Zoisite with Rubellite (Ruby in Zoisite)

Zoisite with inclusions of Hornblende (Anyolite)