Mixed (Sedimentary, Igneous, And Metamorphic)

Conglomerate

Conglomerate (Clastic sedimentary rock)

Mixed tumbled gemstone collection

Varied minerals, likely including amethyst, sodalite/lapis lazuli, quartzite or aventurine, jasper, and agate/chalcedony

Coarse-grained igneous rock, likely granitic pegmatite or weathered granite

Granite/pegmatitic granite; chiefly quartz (SiO₂), feldspar, and dark mica or amphibole

Concrete aggregate surface

Human-made cementitious composite; primarily calcium-silicate-hydrate cement with mixed silicate aggregate

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (Formula: (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Polished decorative stone spheres

Mixed material; individual spheres may be agate, jasper, quartz, or other ornamental minerals

Conglomeratic volcanic breccia

Lithic volcanic breccia, likely andesitic or basaltic

Quartz pebble

Silicon dioxide (SiO2)

Clear Quartz

SiO2 (Silicon Dioxide)

Mica

Mica group (often Muscovite or Biotite)

Clear Quartz

Silicon Dioxide (SiO2)

Polished brown jasper

Jasper (microcrystalline quartz, SiO₂), likely iron-oxide-rich variety

River-rounded landscaping pebbles

Mixed alluvial gravel; commonly quartzite, granite, basalt, sandstone, and quartz

Mookaite Jasper

Silicified radiolarite (SiO2)

Gravel and Pebbles

Unconsolidated rock fragments (clastic sediment)

Mookaite Jasper

Silicified Radiolarite (SiO2)

Granite

Granite (Phaneritic intrusive igneous rock)

Conglomerate

Conglomerate (clastic sedimentary rock)

Mixed rounded river pebbles, probably quartz-rich metamorphic and volcanic rocks

Predominantly quartzite/metachert, with possible rhyolite, sandstone, and iron-stained quartz; exact species cannot be determined confidently from the image

Green aventurine (likely)

Quartz, SiO₂, with green fuchsite mica inclusions

Mixed polished river pebbles, predominantly quartzite and quartz

Quartzite (SiO₂), quartz (SiO₂), with possible feldspar-rich and iron-stained lithologies

Mixed Mineral Collection (with Quartz, Beryl, and host rock)

Silicon Dioxide (Quartz), Be3Al2Si6O18 (Beryl), and associated Schist/Pegmatite

Weathered quartz-rich river pebble

Likely altered granite or granitic gneiss, composed mainly of quartz, feldspar, and minor mica/iron oxides

Black granite (likely polished gabbro or diabase)

Granitoid rock dominated by feldspar, quartz, and dark mafic minerals; exact identification requires testing

Tumbled pink granite or feldspar-rich pebble

Granite; chiefly quartz (SiO₂), feldspar, and minor mica, though the specimen may be pink orthoclase feldspar

Gabbro

Gabbro

Pink Granite

Phaneritic Felsic Igneous Rock (composed primarily of K-Feldspar, Quartz, and Plagioclase)

Amygdaloidal Basalt

Amygdaloidal Mafic Volcanic Rock

Rhyolitic Tuff

Rhyolitic Tuff / Pyroclastic rock

Weathered granite

Granite, a coarse-grained felsic intrusive igneous rock

Weathered granite pebble

Granite, a quartz–feldspar–mica plutonic rock

Blue-gray granite or granitic gneiss pebble

Granite, chiefly quartz, feldspar, and biotite/amphibole

Tumbled granite pebble

Granite, primarily quartz–feldspar–mica aggregate

Polished granite cobble

Granite, typically quartz–feldspar–biotite granite

Tumbled granite or granitic gneiss

Granite; primarily quartz, alkali feldspar, plagioclase, and mica

Granodiorite

Phaneritic-textured Intrusive Granodiorite

Mahogany Obsidian

Volcanic glass containing Magnetite/Hematite

Tumbled polymictic stone, likely jasper-bearing conglomerate

Siliciclastic conglomerate with microcrystalline quartz (jasper/chert) and altered volcanic or feldspathic clasts

Polymictic conglomerate

Lithified polymictic conglomerate; clasts likely quartzite, granite, and volcanic rock in a dark matrix

Bauxite (Iron-stained Chert / Ironstone Aggregate)

Hydrous aluminum oxide mixture (mainly Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Goethite α-Fe3+O(OH))

Yellow Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Devil's Toenail (Fossil Oyster)

Gryphaea arcuata (Calcium Carbonate, CaCO3)