Mixed (Predominantly Sedimentary And Igneous)

Browse mixed (predominantly sedimentary and igneous) specimens identified by the Rock Identifier community.

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

metamorphic

Banded Gneiss

Gneiss (High-grade metamorphic rock)

metamorphic

Quartz (likely tumbled or naturally water-worn)

Quartz (SiO₂ - Silicon Dioxide)

Mineral

Quartz (specifically Milky Quartz/Quartzite)

Silicon Dioxide (SiO2)

Mineral

Rough Diamond

Diamond (Pure Carbon: C)

mineral

Blue Tiger's Eye

Riebeckite (crocidolite variety)

Mineral

Iron Meteorite

Siderite (Iron-Nickel Alloy), predominantly Kamacite and Taenite (Fe, Ni)

mineral

Black Obsidian and Hematite

Volcanic Glass (SiO2) and Hematite (Fe2O3)

igneous and mineral

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

metamorphic

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Pyrite

Iron Sulfide (FeS2)

mineral

Yellow Chalcedony (Carnelian/Yellow Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Mineral

Blue-dyed Quartz Druzy

Silicon Dioxide (SiO2) with artificial pigment

mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

mineral

Fluorite

Fluorite (Calcium Fluoride, CaF2)

mineral

Carnelian Agate

Carnelian (Silicon Dioxide: SiO2) with iron oxide impurities

mineral

Gneiss

Foliated Metamorphic Rock (Gneiss)

metamorphic

Quartz (possibly milky quartz)

Quartz (Silica; SiO₂)

Mineral

Gneiss

metamorphic

Hematite

Iron(III) oxide (Fe2O3)

mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

mineral

Dendritic Opal (Common Opal)

Amorphous Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions

mineral

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

metamorphic

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

metamorphic

Serpentinite (Serpentine Rock)

Primarily composed of serpentine group minerals, such as antigorite, chrysotile, and lizardite. Chemical formula for serpentine minerals is (Mg,Fe)3Si2O5(OH)4.

Metamorphic

Ocean Jasper

Orbicular Jasper (variety of Chalcedony - SiO2)

Mineral

Garnet (likely Almandine or a blend)

Garnet group: X3Y2(SiO4)3, where X can be Ca, Mg, Fe2+, Mn2+ and Y can be Al, Fe3+, Cr3+. Given the dark, somewhat reddish-brown appearance in the image, it's likely Almandine (Fe3Al2(SiO4)3) or a mix with other iron-rich garnets.

Mineral

Quartz (Milky Quartz)

Quartz (SiO2 - Silicon Dioxide)

Mineral

Garnet (Red Garnet)

Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).

Mineral (specifically, a variety of the mineral species Pyrope-Almandine Garnet)