Rock Identifier

Category

Synthetic Polymer (Polylactic Acid)

Browse synthetic polymer (polylactic acid) specimens identified by the Rock Identifier community.

Learn about Synthetic Polymer (Polylactic Acid) in the encyclopedia

Yttrium Aluminum Garnet

Yttrium Aluminum Garnet

Zincite

Opalite

Lead Feldspar

Dolomite

Zircon

Orange Calcite

Pearl-embellished decorative cross (Pearl (biogenic calcium carbonate, predominantly aragonite) with rhinestone-mounted glass or synthetic gemstones) — gemstone

Pearl-embellished decorative cross

Pearl (biogenic calcium carbonate, predominantly aragonite) with rhinestone-mounted glass or synthetic gemstones

Diamond (Carbon (C)) — gemstone

Diamond

Carbon (C)

White Marble (Recrystallized Calcite (CaCO3)) — metamorphic

White Marble

Recrystallized Calcite (CaCO3)

Green calcite (likely) (Calcite — calcium carbonate, CaCO₃) — mineral

Green calcite (likely)

Calcite — calcium carbonate, CaCO₃

Sapphire (Corundum (Al2O3)) — mineral

Sapphire

Corundum (Al2O3)

Weathered blue-gray calcite/aragonite fragment (Calcium carbonate (CaCO₃), probably calcite; possibly shell-derived aragonite) — mineral

Weathered blue-gray calcite/aragonite fragment

Calcium carbonate (CaCO₃), probably calcite; possibly shell-derived aragonite

Fossiliferous limestone (Calcite-rich limestone (CaCO₃), containing fossil shell or coral fragments) — sedimentary

Fossiliferous limestone

Calcite-rich limestone (CaCO₃), containing fossil shell or coral fragments

Likely calcite-rich limestone or marble (Calcite (CaCO₃); possibly recrystallized limestone (marble)) — metamorphic

Likely calcite-rich limestone or marble

Calcite (CaCO₃); possibly recrystallized limestone (marble)

Peacock Ore (Chalcopyrite) (Chalcopyrite (CuFeS2)) — mineral

Peacock Ore (Chalcopyrite)

Chalcopyrite (CuFeS2)

Strawberry Quartz (Silicon Dioxide (SiO2) with inclusions of Goethite or Hematite) — Mineral

Strawberry Quartz

Silicon Dioxide (SiO2) with inclusions of Goethite or Hematite

Calcite-rich limestone (Limestone, predominantly calcite (CaCO₃), possibly recrystallized) — sedimentary

Calcite-rich limestone

Limestone, predominantly calcite (CaCO₃), possibly recrystallized

Tumbled amber (Fossilized tree resin; predominantly polymerized diterpenoid resin (succinite when Baltic-type)) — fossil

Tumbled amber

Fossilized tree resin; predominantly polymerized diterpenoid resin (succinite when Baltic-type)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Fossiliferous Limestone (Coquina / Shell Limestone) (CaCO3 (Calcium Carbonate)) — sedimentary

Fossiliferous Limestone (Coquina / Shell Limestone)

CaCO3 (Calcium Carbonate)

Honey Calcite (Calcium Carbonate (CaCO3)) — mineral

Honey Calcite

Calcium Carbonate (CaCO3)

Black Tourmaline (Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)) — mineral

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Fossilized bivalve or brachiopod fragment (Indeterminate fossil shell, likely calcitic or aragonitic carbonate) — fossil

Fossilized bivalve or brachiopod fragment

Indeterminate fossil shell, likely calcitic or aragonitic carbonate

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Fossil-bearing limestone (Bioclastic limestone, likely containing bivalve or brachiopod impressions) — fossil

Fossil-bearing limestone

Bioclastic limestone, likely containing bivalve or brachiopod impressions

Fossiliferous limestone (Bioclastic carbonate rock; predominantly calcite (CaCO₃), with fossil shell fragments) — sedimentary

Fossiliferous limestone

Bioclastic carbonate rock; predominantly calcite (CaCO₃), with fossil shell fragments

Orange calcite pieces on blue calcite or aragonite matrix (Calcite, CaCO₃; blue coloration likely trace-element-bearing calcite (possibly aragonite)) — mineral

Orange calcite pieces on blue calcite or aragonite matrix

Calcite, CaCO₃; blue coloration likely trace-element-bearing calcite (possibly aragonite)

Peacock Ore (Bornite (Cu5FeS4) or iridescent Chalcopyrite (CuFeS2)) — mineral

Peacock Ore

Bornite (Cu5FeS4) or iridescent Chalcopyrite (CuFeS2)

Fossiliferous limestone (Bioclastic carbonate rock, chiefly calcite (CaCO₃)) — sedimentary

Fossiliferous limestone

Bioclastic carbonate rock, chiefly calcite (CaCO₃)

Unidentified small rock fragments (Indeterminate from image; possibly quartz-rich material) — mineral

Unidentified small rock fragments

Indeterminate from image; possibly quartz-rich material

Quartz-rich crystalline rock, likely drusy quartz on matrix (Quartz (SiO₂), possibly intergrown with calcite or feldspar matrix) — mineral

Quartz-rich crystalline rock, likely drusy quartz on matrix

Quartz (SiO₂), possibly intergrown with calcite or feldspar matrix

Yellow Calcite (Calcium Carbonate (CaCO3)) — mineral

Yellow Calcite

Calcium Carbonate (CaCO3)

Fossiliferous Limestone (Coral Fossil) (Scleractinian Coral in Calcium Carbonate (CaCO3)) — sedimentary

Fossiliferous Limestone (Coral Fossil)

Scleractinian Coral in Calcium Carbonate (CaCO3)

Banded calcite (travertine or calcite-rich carbonate) (Calcite, CaCO₃; likely banded travertine or recrystallized limestone) — sedimentary

Banded calcite (travertine or calcite-rich carbonate)

Calcite, CaCO₃; likely banded travertine or recrystallized limestone

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Rounded white pebble, likely quartz-rich rock (Most consistent with quartzite or milky-quartz pebble; exact identification requires testing) — sedimentary

Rounded white pebble, likely quartz-rich rock

Most consistent with quartzite or milky-quartz pebble; exact identification requires testing

Calcite specimen (Calcite (calcium carbonate, CaCO₃)) — mineral

Calcite specimen

Calcite (calcium carbonate, CaCO₃)

Amber (Copal) (Organic gemstone, fossilized tree resin (often immature amber or copal)) — Mineral

Amber (Copal)

Organic gemstone, fossilized tree resin (often immature amber or copal)

Amber (Black) (Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)) — Mineraloid

Amber (Black)

Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)

Fossiliferous limestone (Calcarenite/bioclastic limestone, predominantly calcite (CaCO₃)) — sedimentary

Fossiliferous limestone

Calcarenite/bioclastic limestone, predominantly calcite (CaCO₃)

Tumbled fossil-bearing limestone (likely crinoid or shell fragment) (Fossil carbonate; predominantly calcite (CaCO₃)) — fossil

Tumbled fossil-bearing limestone (likely crinoid or shell fragment)

Fossil carbonate; predominantly calcite (CaCO₃)

Polished onyx marble (banded calcite) (Calcite, CaCO₃; commonly called Mexican onyx or cave onyx) — metamorphic

Polished onyx marble (banded calcite)

Calcite, CaCO₃; commonly called Mexican onyx or cave onyx

Tumbled quartz (likely milky or iron-stained quartz) (Quartz, silicon dioxide (SiO₂)) — mineral

Tumbled quartz (likely milky or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)