Sedimentary Or Metamorphic (Base Substrate)

Fuchsite

Chrome-bearing Muscovite [K(Al,Cr)2(AlSi3O10)(OH)2]

Citrine

Silicon Dioxide (SiO2)

Fossilized Shark Tooth (Otodus obliquus)

Otodus obliquus (Mineralized Apatite / Bio-apatite)

Chert Arrowhead (Jasper)

Chert (Cryptocrystalline Quartz, SiO2)

Sandstone (Quartzose)

Arenite (composed primarily of SiO2)

Biotite or Phlogopite Mica

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

Red Aventurine / Orange Quartzite

Silicon Dioxide (SiO2) with hematite/goethite inclusions

Pink Jade (Dyed Quartzite)

Silicon Dioxide (SiO2) - primarily Quartzite or Quartz

Painted Rock

Weathered Sedimentary Rock (Painted)

Heliotrope (Bloodstone)

Chalcedony quartz variety (SiO2) with hematite or jasper inclusions

Sandstone

Arenite (SiO2 based sedimentary rock)

Schist

Mica Schist (Metamorphic Rock)

Corundum (Sapphire/Ruby in Matrix)

Aluminium oxide (Al2O3)

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (SiO2 based)

Quartzite

Quartzite (SiO2)

Limestone Breccia

Sedimentary Breccia (Calcareous)

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.

Sandstone (lithic wacke/conglomerate mix)

Clastic Sedimentary Rock (SiO2 with lithic fragments)

Sandstone or Quartzite

Sandstone or Quartzite (SiO2 primarily)

Epidote

Epidote (Ca2(Al, Fe)3(SiO4)3(OH))

Red Garnet

Pyrope or Almandine (Silicate group, X3Y2(SiO4)3)

Muscovite Mica

KAl2(AlSi3O10)(OH)2

Epidotite (Unakite-related)

Epidote-rich rock

Citrine (Heat-treated Amethyst)

Silicon Dioxide (SiO2) with iron impurities

K2 Jasper (K2 Stone)

Azurite in Granite / Quartzite

River Stone (Sandstone or Siltstone)

Sedimentary Rock (Clastic)

Muscovite

Muscovite (KAl2(AlSi3O10)(OH)2)

Fossiliferous Limestone

Carbonate sedimentary rock (CaCO3)

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Epidote

Epidote (Ca2(Al,Fe)3(SiO4)3(OH))

Emerald in Matrix

Emerald (variety of Beryl) - Be3Al2(SiO3)6

Yellow Aventurine

Silicon Dioxide (Quartz with inclusions), SiO2

Limestone Pebble

Calcium Carbonate (CaCO3)

Rainbow Moonstone with Black Tourmaline

White Labradorite with Schorl (Na,Ca)(Al,Si)4O8

Sandstone

Arenite (SiO2 based)

Basalt with Epidote (Greenstone)

Epidote-bearing Metabasalt

Quartzite Pebble

Quartzite (SiO2)

Bornite (Peacock Ore)

Bornite (Cu5FeS4)

Shale or Mudstone (Based on appearance)

Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)

Biotite (Mica)

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