Merlinite (dendritic opal)
Common opal (hydrated amorphous silica, SiO₂·nH₂O) with dark manganese-oxide dendrites; the trade name “merlinite” is also applied to other patterned stones.
sedimentary
Category
Mineral (Impactite)
Browse mineral (impactite) specimens identified by the Rock Identifier community.
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Morganite and Aquamarine (Beryl) Bracelet
Beryllium aluminum silicate, Be3Al2(SiO3)6
gemstone
Bicolor Quartz Tumble
Silicon Dioxide (SiO2)
mineral
Limonite
FeO(OH)·nH2O
mineral
Selenite (variety of Gypsum)
Calcium sulfate dihydrate (CaSO4·2H2O)
mineral
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Epidote
Calcium aluminum iron silicate (Ca2(Al, Fe)3(SiO4)3(OH))
mineral
Basalt with Vesicular/Amygdaloidal Alteration
Extrusive Igneous Rock (Mafic)
igneous
Basalt with Amygdule
Aphanitic Mafic Volcanic Rock (Basalt) with Zeolite/Quartz Infill
igneous
Epidote
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
mineral
Hematite (likely Botryoidal or Specularite variant)
Iron(III) oxide (Fe2O3)
mineral
Hematite
Iron(III) oxide (Fe2O3)
mineral
Hematite
Hematite (Iron(III) oxide, Fe2O3)
mineral
Native Copper Nugget
Native Copper (Cu)
mineral
Geode (Calcite or Quartz)
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)
sedimentary
Sandstone
Arenite
sedimentary
Blue Chalcedony
Silicon Dioxide (SiO2)
mineral
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Amphibolite
Amphibolite, composed mainly of amphibole and plagioclase feldspar
metamorphic
Blue Apatite
Fluoroapatite (Ca5(PO4)3F)
mineral
Likely serpentinite (greenstone pebble)
Serpentinite, composed mainly of serpentine-group minerals (e.g., lizardite, chrysotile, or antigorite)
metamorphic
Biotite gneiss (probable)
Foliated quartz–feldspar–mica gneiss; commonly containing biotite mica, quartz, and plagioclase/alkali feldspar
metamorphic
Copper Ore
Mixed copper sulfides/oxides in gangue matrix
mineral
Gravel and Pebbles
Unconsolidated rock fragments / detrital sediment
sedimentary
Fossilized Shark Tooth
Chondrichthyes (Class)
fossil
Fossil Shark Tooth
Carcharodon or Carcharias fossil (Vertebrate Fossil)
sedimentary
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
mineral
Weathered granite or granitic gneiss
Granite/granitic gneiss, composed mainly of quartz, feldspar, and mica
igneous
Mica schist
Schist dominated by muscovite/biotite mica, commonly with quartz and feldspar
metamorphic
Weathered granite pebble
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Unidentified gray mineral/rock fragment
Indeterminate from the photograph; possibly a quartz- or feldspar-bearing rock fragment
mineral
Tiny metallic-looking mineral or rock fragment
Unidentifiable from the image; possibly a small metallic mineral grain
mineral
Possible green glassy mineral pebble
Undetermined; possibly green aventurine (quartz) or another green mineral
mineral
Granite
Intrusive Felsic Igneous Rock
igneous
Banded Gneiss
Gneiss
metamorphic
Banded Sandstone (River Cobble)
Arenite Sandstone with heavy mineral layering
sedimentary
Gneiss (foliated metamorphic rock)
Gneiss
metamorphic
Weathered mica schist (tentative)
Mica schist, likely muscovite–biotite schist with quartz and feldspar
metamorphic
Yellow-brown stone or mineral fragment
Unidentified; the image does not show enough detail for a reliable identification
mineral
Small pale mineral fragment, possibly calcite
Unidentified; calcite (CaCO₃) is one possibility
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Sandstone with Quartz/Calcite druse
Arenite with druse (SiO2 or CaCO3)
sedimentary