Mineral (Or Mineraloid If Microcrystalline)

Chert (and its variety Flint)

Silicon Dioxide (SiO2) - Microcrystalline or cryptocrystalline Quartz

Chert (specifically Tan/Brown Chert)

Chert (SiO2)

Mixed Chalcedony and Jasper Bracelet (possibly 'Ocean Jasper' or similar banded variety for brown beads, and blue/grey Chalcedony for the translucent beads)

Chalcedony (SiO2), Jasper (SiO2 with impurities)

Basalt River Pebble

Basalt (Aphanitic Mafic Volcanic Rock)

Chert (Jasper-bearing)

Microcrystalline silica (SiO2) with iron oxide inclusions

Yellow Quartzite River Cobble

Meta-quartzite (SiO2 with iron oxide staining)

Carnelian

Carnelian (SiO2 with Iron oxide impurities)

Petrified Wood

Silicified Wood (SiO2 - Quartz/Chalcendony replacing organic matter)

Yellow Jade (often Serpentine or Dolomite)

Primarily Serpentine (Mg3Si2O5(OH)4) or Dolomite (CaMg(CO3)2), though the term 'yellow jade' is also sometimes applied to varieties of true nephrite or jadeite.

Ironstone Nodule (Ironstone Concretion)

Siderite-rich Mudstone (FeCO3) or Limonite (FeO(OH)·nH2O)

Jasper (yellow/cream variety)

SiO₂ (Cryptocrystalline Quartz)

Blue Tiger's Eye

Crocidolite (fibrous riebeckite) silicified to Quartz (SiO2)

Chert (with Quartz Vein)

Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)

Petrified Wood

Silicified Wood (primarily SiO₂ - Silicon Dioxide)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Black Onyx

Silicon dioxide (SiO2) with parallel banded structure

Banded Iron Formation (BIF)

Banded Iron Formation

Limestone

Calcium Carbonate (CaCO3)

Jadeite Jade

Jadeite (Sodium Aluminum Silicate, NaAlSi₂O₆)

Petrified Wood

Silicified Wood (SiO2)

Chert (Iron-stained)

Microcrystalline silica (SiO2) with trace Iron oxide (Fe2O3)

Brecciated Jasper

Silicon Dioxide (SiO2) with varying mineral inclusions (Iron Oxide, Hematite, Clay)

Jasper (Iron-rich Chalcedony)

Jasper (Microcrystalline Silicon Dioxide, SiO2 plus iron oxide impurities)

Carnelian (Chalcedony variety)

SiO2 (Silicon Dioxide)

Slate

Slate (a fine-grained, foliated metamorphic rock). Mineral composition: Primarily composed of mica minerals (muscovite, chlorite, sericite) and quartz, with minor amounts of hematite, pyrite, and other accessory minerals.

Banded Jasper (possibly "Picture Jasper")

Jasper (a microcrystalline variety of Quartz / Silicon Dioxide - SiO2)

Quartz Vein in Gneiss or Basalt

Milky Quartz (SiO2) within Metamorphic Host Rock

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

River Rock (River Cobbles)

Fluvial Conglomerate Clasts (primarily composed of various minerals such as Quartz, SiO2)

Green Aventurine (Green Quartz)

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Red Jasper or Chert

Jasper (SiO2, a variety of chalcedony with iron oxide impurities), Chert (SiO2)

Chert Nodule in Limestone

Chert (Microcrystalline Quartz, SiO2) and Limestone (Calcium Carbonate, CaCO3)

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Travertine (used in construction, not a 'specimen' in situ)

Travertine

Slate

Foliated Metamorphic Rock (primarily composed of Muscovite, Chlorite, and Quartz)

Ocean Jasper (Orbicular Jasper)

Silicon Dioxide (SiO2) with iron and magnesium inclusions

Mixed Gemstone Bracelet

Mixed natural minerals and rocks (e.g., Rhodonite, Malachite, Sodalite, Rose Quartz, Black Tourmaline, Quartz/Chalcedony variants)

Red Jasper (with Quartz Veins)

Jasper (var. chert, SiO₂)

Jasper

Jasper (Silica-rich microcrystalline Quartz, SiO2 with Fe2O3 impurities)

Petrified Wood

Silicified Wood (SiO2)

Green Aventurine and Clear Quartz

Aventurine (variety of Quartz - SiO2) and Quartz (SiO2)

Chert / Flint (a variety of Chert)

Chert (SiO2)