Mineral (Tectosilicate)

Citrine

SiO2 (Silicon Dioxide)

Fluorite (Rainbow or Multi-colored Fluorite)

Fluorite (Calcium Fluoride - CaF2)

Slate

Foliated Metamorphic Rock (primarily composed of quartz, illite, chlorite, and micas)

Granite

Granite

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.

Turquoise and Hematite

CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Fe2O3 (Hematite)

Quartz-veined Sedimentary Rock

Hydrothermally veined Clastic Sedimentary Rock (SiO2 veins in Matrix)

Sandstone (likely with Quartz Veining)

Arenite (primarily SiO2)

Fluorite (Rainbow/Purple Fluorite)

Calcium Fluoride (CaF2)

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic extrusive volcanic rock with secondary mineral infilling)

Hematite

Hematite (Fe2O3)

Chrysocolla

Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O)

Schist with Biotite and Quartz

Biotite-Quartz Schist (Fe,Mg,Al silicate mix)

Granite

Granite

Pebble

Clast (specifically a granule or small pebble)

Yellow Ochre / Limonite

Limonite (FeO(OH)·nH2O)

Orthoclase Feldspar

Potassium aluminum silicate (KAlSi3O8)

Limonite (Iron Stone/Gossen)

Limonite (FeO(OH)·nH2O)

Limonite

Limonite (Hydrated iron oxide mixture, FeO(OH)·nH2O)

Turquoise

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

Sulfur on Quartz

Native Sulfur (S8) with Quartz (SiO2)

Granite or Pegmatite with Mica

Granitoid

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2) with miscellaneous inclusions

Milky Quartz with Mineral Inclusions

Quartz (Silicon Dioxide, SiO2)

Gemstone Sand (Mineral Assortment)

Mixed Mineral Concentrates (Commonly including Quartz SiO2, Garnet X3Y2(SiO4)3, and Tourmaline (Na,Ca)(Li,Mg,Al)3(Al,Fe,Mn)6(BO3)3(Si6O18)(OH,F)4)

Garden Quartz (Lodalite)

Silicon Dioxide (SiO2) with mineral inclusions

Banded Gneiss (with possible weathered sulfide or iron staining)

Gneiss, potentially with iron oxide/hydroxide staining (e.g., limonite) or weathered sulfides

Quartz (Druzy)

Silicon Dioxide (SiO2)

Jadeite and Mixed Gemstones (Ruby, Sapphire, Emerald)

Jadeite (NaAlSi2O6), Corundum (Al2O3), Beryl (Be3Al2(Si6O18))

Chrysocolla

Hydrated copper phyllosilicate mineral (Cu,Al)2H2Si2O5(OH)4·n(H2O)

Limonite Concretion (Ironstone)

Limonite (Hydrated Iron(III) Oxide-Hydroxide, FeO(OH)·nH2O)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated Iron Oxide)

Limonite (vibrant yellowish-brown iron oxide)

Limonite (FeO(OH)·nH2O)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Lapis Lazuli

Lapis Lazuli (Complex silicate rock containing Lazurite (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, Calcite, and Pyrite)

Bauxite

AlOx(OH)3-2x (mixture of Gibbsite, Boehmite, and Diaspore)

Lapis Lazuli

Na6Ca2(Al6Si6O24)(S,SO4,Cl)1-2 (primarily containing Lazurite with inclusions of Calcite and Pyrite)

Granite

Granite (Felsic intrusive igneous rock)

Lapis Lazuli (Raw)

Lazurite-rich metamorphic rock; Na3Ca(Al3Si3O12)S

Heat-Treated Amethyst (Commercial Citrine)

Silicon Dioxide (SiO2) - Macro-crystalline Quartz

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Gneiss (specifically a Granitic Gneiss specimen)

Gneiss (high-grade metamorphic rock primarily composed of Quartz, Feldspar, and Biotite/Amphibole)