Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)

Greenstone (Epidote/Chlorite-rich Metabasalt)

Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))

Rough Star Sapphire (Corundum)

Al2O3 (Aluminum Oxide)

Quartz / Rock Crystal

Silicon Dioxide (SiO2)

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Amber

Succinite (fossilized tree resin)

Labradorite

Labradorite ((Ca, Na)(Al, Si)4O8)

Chrysocolla

Hydrated copper silicates (Cu, Al)2H2Si2O5(OH)4·nH2O

Milky Quartz (or Iron-Stained Quartz)

Quartz (Silicon Dioxide, SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Basalt

Basalt (Aphanitic mafic volcanic 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.

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Turquoise

Hydrated phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O

Quartz (milky quartz variety)

Quartz (SiO₂)

Ruby in Fuchsite

Corundum (Al2O3) in Fuchsite (K(Al,Cr)3Si3O10(OH)2)

Amethyst

Amethyst (Silicon Dioxide with Iron impurities, SiO2)

Slag (Industrial Byproduct)

Artificial silicate/iron byproduct

Quartz (likely)

Quartz (SiO2 - Silicon Dioxide)

Biotite Schist

Biotite Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)

Quartz (Specifically Clear to Smoky Quartz point)

Silicon Dioxide (SiO2)

Polymer Clay (Mock Mineral)

Polyvinyl chloride (PVC) with plasticizers and pigment

Ironstone (likely Limonite or Goethite)

Ferruginous sedimentary rock (FeO(OH)·nH2O)

Milky Quartz

Silicon Dioxide (SiO2)

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

Sandstone (Ferruginous)

Arenite with Iron Oxide (Fe2O3) cement

Mica Schist

Mica Schist (predominantly Muscovite or Biotite sheet silicates)

Fossilized Gastropod (Snail)

Class Gastropoda (internal mold or 'steinkern')

Garnet Schist or Garnet-bearing Quartzite

Metamorphic rock containing Almandine Garnet (Fe3Al2(SiO4)3) and Quartz (SiO2)

Citrine Geode Fragment

Citrine (Silicon Dioxide with Iron Impurities), SiO2

River Pebble (Likely Chert or Fine-Grained Sandstone/Quartzite)

Siliciclastic clast (likely Chert or Quartzarenite/Quartzite pebble)

Agate (specifically Lake Superior Agate style or Banded Chalcedony)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Smoky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide staining/cementing)

Sandstone

Arenite (primarily SiO2)

Hypersthene

Hypersthene ((Mg,Fe)SiO₃)

Fulonite (Fulgurite-like)

Fulgurite (SiO2 fused silica/lechatelierite)

Quartz (chalcedony variety) or Limestone with Quartz Veins

SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)

Siltstone/Sandstone (possibly Wonderstone or Picture Sandstone)

Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide inclusions)

Sandstone (with Iron Staining)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

Petrified Wood

Silicified wood (Quartz/Chalcedony)