Man Made Material, Not A Natural Rock Or Mineral Specimen

River Cobble (Diorite or Meta-volcanic with Quartz Veining)

Diorite (with SiO2 quartz veins)

Rounded granitic gneiss or granite cobble

Granite; primarily quartz, plagioclase and potassium feldspar with biotite/hornblende

Pegmatitic pink feldspar–quartz rock

Granitic pegmatite; chiefly microcline/orthoclase feldspar (KAlSi₃O₈), quartz (SiO₂), and minor mica

Weathered sandstone or iron-stained sedimentary pebble

Quartz-rich sandstone; exact identification requires a fresh surface and tests

Yellow Quartz (Citrine/Yellow Jasper)

Silicon Dioxide (SiO2)

Earth

Terra / Earth

Granite

Granite (Phaneritic igneous rock)

Vesicular Basalt (Iron Scoria)

Aphanitic Mafic Igneous Rock with Vesicular Texture

Chert (River Cobble)

Chert (Cryptocrystalline Quartz, SiO2)

Blue Quartz with Graphite/Tourmaline Inclusions

Silicon Dioxide (SiO2) with Carbon (C) or Schorl elements

Granite

Granite

Nuummite

Nuummite (Orthorhombic amphiboles: Anthophyllite and Gedrite)

Sandstone (Ferruginous)

Clastic Sedimentary Rock (SiO2 with Fe2O3)

Conglomerate

Conglomerate (Sedimentary Clastic Rock)

Ocean Jasper

SiO2 (Silicon Dioxide) - Chalcedony variety

Shale or Mudstone (Based on appearance)

Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)

Possibly tumbled dark stone or mineral specimen

Indeterminate from image; possibly black tourmaline, basalt, or another dark silicate

Pink Fluorite

Fluorite (Calcium Fluoride) - CaF2

Quartzite River Cobble

Quartzite (primarily SiO2)

Sandstone

Sandstone (lithified sand)

Banded sandstone pebble

Lithic or quartz-rich sandstone; exact composition requires testing

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Polished orbicular jasper / brecciated jasper

Jasper, microcrystalline quartz (SiO₂), with iron-oxide and clay-rich inclusions

Iron-stained quartz-bearing rock

Quartz (SiO₂), likely in a limonite/goethite-rich matrix

Sandstone

Arenite (primarily SiO2)

Chert (concretionary/nodular variant)

Microcrystalline Quartz (SiO2) with possible fossil or mineral inclusions

Likely quartz-rich metamorphic rock (quartzite or milky quartz)

Quartzite; predominantly quartz (SiO₂), possibly with feldspar and iron-oxide staining

Likely weathered basalt or iron-rich volcanic rock

Basalt; primarily plagioclase feldspar, pyroxene, and possibly olivine with iron-oxide alteration

Quartz Pebble

Silicon Dioxide (SiO2)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Green Quartz (Prasiolite)

Crystalline Silicon Dioxide (SiO2) with iron impurities

Citrine

Citrine (Silicon Dioxide, SiO2)

Weathered iron-rich sandstone or laterite

Ferruginous sandstone; chiefly quartz (SiO₂) cemented or stained by iron oxides such as hematite and goethite

Yellow Quartz

Silicon Dioxide (SiO2)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Iron-rich weathered rock (likely limonite/goethite concretion)

Limonite–goethite mixture; chiefly FeO(OH)·nH₂O

Rounded granitic pebble

Granite, likely biotite granite or granodiorite

Sandstone

Arenite (SiO2 based)

Granite

Phaneritic intrusive igneous rock

Sandstone (Pebble)

Sandstone (SiO2 with matrix/cement)

Sandstone

Arenite

Sandstone

Arenite (mostly SiO2)