Mineral, Often A Rock Given Its Aggregate Nature

White Topaz

Al2SiO4(F,OH)2 (Aluminium Silicate Fluoride Hydroxide)

Basalt (Weathered River Pebble)

Extrusive Igneous Rock

Generic Pebble / Rock Fragment

Lithic fragment / Weathered rock

Silicon (Industrial Grade)

Elemental Silicon (Si)

Gossan (with Limonite/Hematite coating)

Ferruginous Gossan (Fe2O3·nH2O / Fe2O3)

Biotite Mica

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

Gold (Elemental Metal)

Gold (Au)

Sandstone

Clastic Sedimentary Rock

Basalt Pebble

Extrusive Igneous Rock

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2

Granite

Intrusive Igneous Rock

Basalt

Extrusive Igneous Rock (Mafic)

Limestone (Weathered)

Sedimentary carbonate rock, primarily calcium carbonate (CaCO3)

Chert (Jasper)

Silicon Dioxide (SiO2)

Unknown Organic Object (likely a berry or fruit)

Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.

Basalt (Vesicular/Waterworn)

Basalt (Mafic Extrusive Igneous Rock)

Granite

Phaneritic plutonic rock (Quartz, Feldspar, Mica)

Conglomerate

Conglomerate (a clastic sedimentary rock)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Shale

Argillite / Shale

Smelter Slag

Anthropogenic Silicate Slag

Specular Hematite (Specularite)

Iron(III) oxide (Fe2O3)

Conglomerate

Conglomerate (SiO2 matrix with varying clasts)

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.

Granite

Intrusive Igneous Rock

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets

Copper Ore (Malachite/Chrysocolla bearing)

Cupriferous rock containing secondary copper minerals like Cu2CO3(OH)2

Milky Quartz

Silicon Dioxide (SiO2)

Concrete rubble

Anthropogenic conglomerate

Red Jasper

Jasper (a cryptocrystalline variety of Quartz, SiO₂)

Chert Nodules (Limonitic Chert)

Cryptocrystalline Quartz (SiO2) with Hydrated Iron Oxides

Milky Quartz

Silicon Dioxide (SiO2)

Satin Spar Selenite

Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)

Silicon Carbide (Carborundum)

Silicon Carbide, SiC

Petrified Wood

Silicified Wood (primarily Quartz or Chalcedony, SiO2)

Quartzite Pebble

Quartzite (mostly SiO2)

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Gray Basalt

Basalt (Mafic Extrusive Igneous Rock)

Greenstone with Pyrite inclusions

Greenschist / Meta-volcanic rock with Iron Disulfide (FeS2)

Quartz Pebble

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone Pebble

Arenite (Siliclastic sedimentary rock)