Mineralized Fossil

Kunzite

Spodumene (LiAlSi2O6)

Epidote with Magnetite/Hematite inclusions

Epidote (Ca2(Al2,Fe3+)(SiO4)3(OH)) with Iron Oxides

Collection of Minerals and Ores

Various (e.g., Uraninite (U3O8), Carbon (C), Native Gold (Au), Hematite (Fe2O3), Galena (PbS), etc.)

Hematite Mineral Ore

Iron(III) oxide (Fe2O3)

Pearl (Biogenic Mineral)

Calcium Carbonate (primarily Aragonite) with Conchiolin; CaCO3

Pearl (as a Biogenic Mineral)

Calcium Carbonate (mostly Aragonite) with Conchiolin; CaCO3

Desert Rose

Gypsum (variety Selenite) or Barite: CaSO4 · 2H2O

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Limonite (Ironstone Concretion)

Limonite: FeO(OH)·nH2O

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Fluorite

Calcium Fluoride (CaF2)

Yellow Ochre / Limonite

Limonite (FeO(OH)·nH2O)

Orthoclase Feldspar

Potassium aluminum silicate (KAlSi3O8)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Obsidian

Volcanic Glass (SiO2)

Limonite (Ironstone)

Limonite (mixture of hydrated iron(III) oxide-hydroxides)

Limonite (Iron Stone/Gossen)

Limonite (FeO(OH)·nH2O)

Snowflake Obsidian

Obsidian with Cristobalite inclusions (SiO2)

Bauxite

Bauxite (Al2O3·2H2O mixed with iron oxides)

Limonite

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

Limonite (Iron Ore)

Limonite; FeO(OH)·nH2O

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated Iron Oxide)

Limonite Concretion (Ironstone)

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

Limonite (vibrant yellowish-brown iron oxide)

Limonite (FeO(OH)·nH2O)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Fluorite

Calcium Fluoride (CaF2)

Limonite / Ironstone

Hydrated ferric oxide (FeO(OH)·nH2O)

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)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Greenstone (Amygdaloidal Basalt)

Amygdaloidal Basalt (frequently composed of Plagioclase Feldspar, Pyroxene, and Olivine with Chlorite inclusions)

Quartz Pebbles

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)

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic volcanic rock)

Shale or Slate with Quartz Veins

Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins

Red Sandstone

Arenite (Ferruginous Sandstone)

Turquoise in Matrix

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

Fuchsite

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

Limonite Geode (Ironstone Concretion)

Limonite [FeO(OH)·nH2O] with possible Quartz or Calcite interior

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.

Schist with Biotite and Quartz

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