Anthropogenic Specimen (Man Made Material)

Quartz (pebble)

Quartz (SiO₂)

Chalk

Calcium Carbonate (CaCO3)

Granite

Granite

Bismuth Crystal

Bismuth (Bi)

Granite

Granite (a phaneritic intrusive igneous rock consisting mainly of quartz, alkali feldspar, and plagioclase)

Grey Granite

Phaneritic Felsic Intrusive Igneous Rock

Oak-grain Laminate (Industrial/Decorative Furniture Finish)

Melamine Resin-impregnated Decorative Paper on Particleboard (Cellulose/Thermosetting Plastic)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Sunstone

Aventurine Feldspar (Plagioclase Feldspar with inclusions)

Quartz (in a rock matrix)

Quartz (SiO2)

Quartz Geode/Cluster

Quartz (SiO2)

Veined Quartz

SiO2 (Silicon Dioxide)

Moonstone

Orthoclase Feldspar (formula: (K,Na)AlSi3O8)

Citrine Quartz

Quartz (SiO2) - specifically, a variety of macrocrystalline quartz

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Limonite (Iron Ore)

Hydrous Iron Oxide (goethite, lepidocrocite)

Quartzite Pebble

Quartzite (SiO2)

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)

Flint

Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)

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.

Geode (Unopened)

Silica-rich Concretion (primarily SiO2)

Painted Pet Rock (Quartzite/Sandstone base)

Silicon Dioxide (SiO2) with anthropomorphic acrylic embellishments

Chert (specifically Gray/Blue-Gray Chert)

Chert (SiO2)

Jasper (yellow/cream variety)

SiO₂ (Cryptocrystalline Quartz)

Sandstone (Ferruginous)

Arenite (with Iron Oxide)

Amethyst Geode/Cluster

Quartz (SiO2) - variety Amethyst

Limestone

Calcium Carbonate (CaCO3)

Ambergris (Geological/Organic Specimen)

Ambra grisea (Produced by Physeter macrocephalus)

Pyrite

Iron Disulfide (FeS2)

Native Silver

Silver (Ag)

Orbicular Granite (specifically Mustard or Yellow Tonalite/Granodiorite)

Orbicular Quartz Diorite / Tonalite

Calcite

Calcite (CaCO3)

Chert

Microcrystalline silica (SiO2)

Granite (tumbled pebble)

Granite (Plutonic Igneous Rock)

Pebble (likely Quartz or Chert)

SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Coquina or Fossiliferous Limestone

Fossiliferous Calcarenite (CaCO3)

Chert (with Limestone/Dolomite host)

Microcrystalline Quartz (SiO2)

Ammonite Fossil

Ammonoidea (primarily composed of Calcite, CaCO3)

Tektite (Indochinite)

Tektite (SiO2 + Al2O3, Glassy Melts)

Calcite

Calcite (CaCO3)

Quartz (likely tumbled or naturally water-worn)

Quartz (SiO₂ - Silicon Dioxide)