Mineral Precipitate (Anthropogenic Context)

Schist (Micaceous)

Mica Schist

Tree Agate

Silicon dioxide (SiO2)

Lepidolite

Lepidolite - K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2

Greenstone (Amygdaloidal Basalt)

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

Arsenopyrite with Schist Matrix

Arsenopyrite (FeAsS)

Gold

Native Gold (Au)

Quartz (Milky/Rose variety)

Silicon Dioxide (SiO2)

Pink Granite

Granite (Phaneritic Quartz-Feldspar Rock)

Gneiss

Gneiss

Granodiorite (or Granite) Pebble

Phaneritic Felsic Igneous Pebble

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

Lapis Lazuli

Lapis Lazuli (Complex aggregate mainly of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Sandstone Concretion with Quartz Center

Sedimentary Clastic Rock (SiO2 matrix with Quartz core)

Emerald in Host Rock

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Citrine

SiO2 (Silicon Dioxide)

Sandstone (likely Quartzose Sandstone pebble)

Arenite (primarily SiO2)

Red Jasper

Silicon Dioxide with Hematite impurities (SiO2 + Fe2O3)

Fluorite (Rainbow or Multi-colored Fluorite)

Fluorite (Calcium Fluoride - CaF2)

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic volcanic rock)

Limonite Geode (Ironstone Concretion)

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

Granite

Granite

Quartz Geode

SiO2 (Silicon Dioxide)

Turquoise and Hematite

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

Red Sandstone (Iron-rich)

Ferruginous Sandstone (SiO2 with Iron Oxides)

Sandstone (likely with Quartz Veining)

Arenite (primarily SiO2)

Epidosite

Epidosite (Metasomatic rock consisting mainly of Epidote and Quartz)

Note: Item is not a geological specimen

Homo sapiens (Dermal Appendage: Pilus)

Turquoise in Matrix

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

Malachite

Copper carbonate hydroxide [Cu2CO3(OH)2]

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Orthoclase Feldspar

Orthoclase (KAlSi₃O₈)

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Amygdaloidal Basalt

Vesicular-Amygdaloidal Basalt (Mafic Extrusive)

Lapis Lazuli (Raw)

Lazurite-rich metamorphic rock; Na3Ca(Al3Si3O12)S

Chrysocolla

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

Gold-Bearing Quartz

Auriferous Quartz (SiO2 with native Au)

Schist with Biotite and Quartz

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

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.

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Malachite

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

Lapis Lazuli

Lapis Lazuli (Primary mineral: Lazurite, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Educational Geologic Collection

Mixed Mineral and Rock Collection (Various compositions)