Mineral (Processed Alloy)

Nugget of Native Silver

Native Silver (Ag)

Aragonite Star Cluster

Aragonite (Calcium Carbonate, CaCO3)

Synthetic Ruby (Jewel Bearings)

Synthetic Corundum (Al2O3 doped with Chromium)

Rhodonite

Rhodonite (MnSiO3)

Shark Tooth Fossil

Carcharocles megalodon or similar fossilized elasmobranch tooth

Pyrite (iron pyrite)

Pyrite, FeS₂

Petrified Wood

Silicified Wood (SiO2)

Smoky Quartz

SiO2 (Silicon Dioxide)

Rose Quartz

Silicon Dioxide (SiO2)

Small blue-gray mineral fragment (undetermined)

Unidentified from the image; no reliable mineral identification is possible from color and appearance alone.

Sulfur on Aragonite

Sulfur (S) on Aragonite (CaCO3)

Beaded Gemstone Bracelet

Composite Mineral Assemblage

Fossil Shark Tooth

Selachii fossil

Dyed Blue Agate

Silicon Dioxide (SiO2) with artificial pigment

Mohave Turquoise (Composite/Stabilized)

Hydrated copper aluminium phosphate (CuAl6(PO4)4(OH)8·4H2O) with stabilizing resin and metallic inclusions

Quartz with Mafic Inclusions

Silicon Dioxide (SiO2) with host igneous matrix

Tumbled green aventurine (likely)

Quartz, SiO₂, with green fuchsite mica inclusions

Prehnite

Ca2Al(AlSi3O10)(OH)2 (Calcium Aluminum Silicate)

Fossil Shell

Brachiopod or Mollusk fossil

Tiger's Eye

Quartz Pseudomorph (SiO2 with inclusions of Crocidolite)

Prehnite

Calcium aluminum silicate hydroxide, Ca2Al(AlSi3O10)(OH)2

Hematite

Iron(III) oxide (Fe2O3)

Blue Aventurine

Quartzite with inclusions of Dumortierite (SiO2 + Al7(BO3)(SiO4)3O3)

Quartz (Rutilated)

Silicon Dioxide (SiO2) with Titanium Dioxide (TiO2) inclusions

Blue Aragonite

Aragonite (Calcium Carbonate, CaCO3)

Aquamarine

Beryl (Be3Al2Si6O18), specifically the blue-green variety

Quartz (Common or Milky Quartz)

Silicon Dioxide (SiO2)

Pyrite in Matrix

Iron Sulfide (FeS2)

Limonite Stained Basalt

Hydrated Iron Oxide on Mafic Volcanic Rock (FeO(OH)·nH2O)

Gem-set gold ring

Likely gold alloy set with a colorless gemstone, possibly diamond or clear quartz; the stone cannot be identified reliably from the image

Mica Schist

Schist (primarily Muscovite and Biotite mica)

Aquamarine

Beryl (Be3Al2Si6O18)

Aquamarine

Beryl (Be3Al2Si6O18)

Quartz and Mixed Minerals

Silicon Dioxide (SiO2)

Banded Gneiss

Banded Gneiss (High-grade Metamorphic Rock)

Given the appearance, it's likely a fragment of an igneous or metamorphic rock composed of multiple minerals. Without specific diagnostic features, it's difficult to give a common name other than 'crystalline rock fragment'. If pressed to guess based on the granular, somewhat light and dark speckled appearance, it could be a fragment of granite or a related intrusive igneous rock.

As a rock fragment, it does not have a single scientific mineral name; rather, it's a piece of a rock which is a combination of minerals. If it were granite, its main mineral composition would be quartz (SiO2), feldspar (e.g., KAlSi3O8 - orthoclase, (Na,Ca)(Al,Si)4O8 - plagioclase), and mica (e.g., KAl2(AlSi3O10)(OH)2 - muscovite or K(Mg,Fe)3AlSi3O10(OH)2 - biotite), among others.

Greenstone with Epidote or Quartz veins

Metabasalt (Greenstone facies)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Petrified Wood

Silicified Wood (SiO2)

Coprolite

Fossilized Feces

Granite

Phaneritic plutonic rock (Silica-rich)