Cupronickel (on a 1981 Mexico 20 Pesos coin)
Copper-Nickel Alloy (Cu75Ni25)
Category
Browse mineral based human made alloy specimens identified by the Rock Identifier community.
Cupronickel (on a 1981 Mexico 20 Pesos coin)
Copper-Nickel Alloy (Cu75Ni25)
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Granite (Leucogranite)
Felsic Plutonic Rock (Granite)
Concrete with Aggregate
Composite construction material; primary matrix is Calcium Silicate Hydrate (C-S-H)
Coarse Sandstone
Arenite (SiO2 based)
Diabase (Greenstone)
Diabase (also known as Dolerite)
Chert (Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Sandstone (River Pebble)
Arenite (SiO2 based)
Sandstone with Tafoni Weathering
Arenite (SiO2 based)
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 based)
Pallasite Meteorite
Pallasite (ST-class)
Obsidian
Volcanic Glass (SiO2)
Chert (Flinty variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Sandstone
Arenite (SiO2 based)
Tree Agate
Silicon Dioxide (SiO2) with Dendritic Inclusions
Kidney Stone (Renal Calculus)
Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O
Red Moss Agate (Jasper)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Chert Pebble/Nodule
Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)
Sandstone
Arenite (SiO2 based with mineral cement)
Sandstone
Arenite (SiO2 based)
Sandstone (likely Red/Brown Sandstone)
Arenite (SiO2 based)
Rose Quartz
Silicon Dioxide (SiO2) with trace titanium, iron, or manganese
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
Sandstone
Arenite (SiO2 based)
Sandstone
Arenite (SiO2 based)
Sandstone (Quartz-rich)
Arenite (SiO2 based)
Amethyst (vibrant lilac/purple variety)
Silicon Dioxide (SiO2) with iron impurities
Standing Liberty Quarter (Silver Specimen)
Native Silver alloy (Ag with Cu traces)
Sandstone (Quartzose)
Arenite (SiO2 based)
Aquamarine
Beryl (Be₃Al₂Si‑₆O₁₈)
Aquamarine
Beryl (Be₃Al₂Si₆O₁₈)
Arsenopyrite
Arsenopyrite (FeAsS)
Sandstone
Arenite (SiO2 based)
Banded Onyx (Mexican Onyx / Travertine)
Calcite (CaCO3) - Banded Travertine
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Biotite Mica
Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
Sandstone
Arenite (SiO2 based)
Sandstone with Quarzite clasts
Arenite (SiO2 based)
Chert (Jasper/Flint variety)
Microcrystalline quartz (SiO2)
Sandstone (likely Arkosic or Lithic Sandstone)
Arenite (SiO2 based with mineral inclusions)