Mineral (Biogenic)

Limonite (Ironstone)

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

Limonite (Iron Stone/Gossen)

Limonite (FeO(OH)·nH2O)

Bauxite

Bauxite (Al2O3·2H2O mixed with iron oxides)

Limonite

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

Epidosite

Epidosite (Metasomatic rock consisting mainly of Epidote and Quartz)

Note: Item is not a geological specimen

Homo sapiens (Dermal Appendage: Pilus)

Desert Rose

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

Amygdaloidal Basalt

Vesicular-Amygdaloidal Basalt (Mafic Extrusive)

Malachite

Malachite (Copper Carbonate Hydroxide, Cu2CO3(OH)2)

Pyrite

Iron Disulfide (FeS2)

Fluorite (left), Sodalite (middle), Dumortierite/Tumbled Quartzite (right)

Calcium Fluoride (CaF2), Sodium Aluminum Silicate Chloride (Na8(Al6Si6O24)Cl2), Aluminum Borosilicate (Al7(BO3)(SiO4)3O3)

Green Fluorite

Calcium Fluoride (CaF2)

Quartz Geode

Silicon dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Greenstone (Amygdaloidal Basalt)

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

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)

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)

Educational Geologic Collection

Mixed Mineral and Rock Collection (Various compositions)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Jadeite and Mixed Gemstones (Ruby, Sapphire, Emerald)

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

Sandstone (likely Quartzose Sandstone pebble)

Arenite (primarily SiO2)

Moss Agate

Chalcedony (Silicon Dioxide) with Chlorite or Iron/Manganese inclusions (SiO2)

Quartzite

Quartzite (Primary mineral: Silicon Dioxide, SiO₂)

Sandstone (with potential mineral inclusions)

Clastic sedimentary rock (primarily Quartz, SiO2)

Limonite Geode (Ironstone Concretion)

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

Chrysocolla

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

Lapis Lazuli

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

Sandstone Concretion with Quartz Center

Sedimentary Clastic Rock (SiO2 matrix with Quartz core)

Turquoise in Matrix

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

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

Chrysocolla

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

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Lapis Lazuli (Raw)

Lazurite-rich metamorphic rock; Na3Ca(Al3Si3O12)S

Red Sandstone

Arenite (Ferruginous Sandstone)

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)