Anthropogenic (Man Made Material Processed By Nature)

Sandstone

Clastic sedimentary rock (primarily SiO2)

K2 Azurite Granite / K2 Stone

Granite (igneous rock) with Azurite inclusions (mineral)

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Dyed Quartz Geode

Silicon Dioxide (SiO2) with artificial pigment

Diamond (or Cubic Zirconia)

Crystallized Carbon (C) for Diamond; Zirconium Dioxide (ZrO2) for CZ

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Polished black stone egg, probably black obsidian

Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements

Green Aventurine

Quartz (SiO2) with Fuchsite inclusions

Amygdaloidal basalt (vesicular basalt)

Basalt, commonly containing amygdales of quartz, chalcedony, calcite, or zeolites

Weathered sandstone cobble

Quartz-rich sandstone, primarily SiO₂ with clay/iron-oxide cement

Tumbled blue chalcedony or pale aquamarine-like quartz

Chalcedony (microcrystalline SiO₂), possibly blue quartz; visual identification is uncertain

Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Quartzite River Pebble

Quartzite (SiO2)

Sandstone with Manganese Dendrites

Arenite (mostly SiO2) with Manganese Oxide inclusions (MnO2)

Possible weathered quartz-rich rock or iron-stained mineral fragment

Indeterminate; possibly quartz (SiO₂) with iron-oxide inclusions

Weathered iron-rich sandstone or ironstone cobble

Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides

Rhodochrosite

Manganese Carbonate (MnCO3)

Polished orbicular granite

Granite, chiefly quartz, alkali feldspar, plagioclase, and biotite/amphibole

Pegmatite with quartz, feldspar, mica, and tourmaline

Granitic pegmatite; chiefly quartz (SiO₂), feldspar, muscovite, and black schorl tourmaline (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Chalcedony (gray-white agate)

Microcrystalline quartz, SiO₂

Quartz-rich metamorphic rock (likely mica schist or gneiss)

Quartz–feldspar–mica assemblage; probable biotite schist/gneiss

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (and Flint)

Silicon Dioxide (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Copper-bearing schist (likely bornite/chalcopyrite ore)

Micaceous schist with sulfide minerals, chiefly bornite (Cu₅FeS₄) and/or chalcopyrite (CuFeS₂)

Turquoise Beads

CuAl6(PO4)4(OH)8·4H2O

Diamond

Carbon (C)

Granite

Phaneritic intrusive felsic igneous rock

Black Tourmaline

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of Titanium, Iron, or Manganese

Calcite (commonly referred to as Orange Calcite or Honey Calcite given its color)

Calcite

Dyed Howlite (Turquenite)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Dyed Quartz Crystal

Silicon Dioxide (SiO2) with artificial pigment

Flint

SiO2 (Microcrystalline Quartz / Chert)

Polished greenstone (likely serpentinite)

Serpentinite, chiefly antigorite/lizardite Mg₃Si₂O₅(OH)₄, possibly with magnetite

Likely petrified wood

Silicified wood, chiefly microcrystalline quartz (SiO₂)

Quartz-rich feldspathic rock, likely granite or granitic gneiss

Granite/granitic gneiss; chiefly quartz (SiO₂), feldspar, and minor mica

Quartz geode

Microcrystalline and crystalline quartz (SiO₂), likely chalcedony-lined geode

Prase Quartz on Feldspar

Quartz (Silicon Dioxide, SiO2) with Hedenbergite inclusions on Potassium Feldspar (KAlSi3O8)

Vesicular basalt (possibly scoria)

Basalt; chiefly plagioclase feldspar, pyroxene, and often olivine, with volcanic glass

Titanium Quartz (Rough)

Titanium-included Silicon Dioxide (SiO2 + Ti)

Chert Pebble (Jasper or Agate variety)

Microcrystalline Quartz (SiO2)