Sedimentary To Metamorphic

Beach Pebbles and Quartz Aggregates

Quartz pebbles and biogenic fragments (SiO2, CaCO3)

Calcite

Calcite (CaCO₃, Calcium Carbonate)

Mixed rock and mineral specimen collection

Multiple species, likely quartz (SiO₂), calcite (CaCO₃), feldspar, chert, and assorted volcanic/sedimentary rocks

Milky Quartz

Silicon Dioxide (SiO2)

Tumbled quartz-rich rock, possibly calcite or sandstone

Indeterminate from photograph; likely microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Red coral (polished coral beads)

Corallium spp.; chiefly calcium carbonate (CaCO₃, calcite)

Likely tumbled quartz or chalcedony fragment

Quartz (SiO₂), possibly microcrystalline chalcedony

Tumbled quartz-rich carbonate rock

Likely massive quartz (SiO₂), possibly calcite-bearing marble or limestone

Quartz

Silicon Dioxide (SiO2)

Likely quartz fragment

Quartz (silicon dioxide, SiO₂), possibly milky quartz or quartz-rich rock

Rounded quartz-rich river pebbles

Alluvial gravel; commonly quartzite, chert, and quartz-bearing sandstone fragments

Red Jasper

Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

Polished gemstone tower assortment

Primarily quartz varieties and simulants; apparent amethyst (SiO₂), rose quartz (SiO₂), clear quartz (SiO₂), fluorite (CaF₂), sodalite, malachite, and possibly dyed or composite stones

Quartz Vein in Host Rock (Likely Slate or Shale)

Hydrothermal Quartz (SiO2) in Pelitic host rock

Quartz Vein in Matrix (Breccia / Host Rock with Quartz)

Silicon Dioxide (SiO2) in Host Rock Matrix

Small gold-colored mineral crystal, likely pyrite

Pyrite (FeS₂), tentatively; native gold is a less likely alternative

Metallic sulfide mineral fragment, likely galena

Galena (lead sulfide, PbS), tentative identification

Banded River Cobble with Mafic Dike

Hydrothermally altered Graywacke or Sandstone with Mafic Intrusion

Limonite (Iron Ore)

Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)

Red Jasper

Jasper (Silicon Dioxide, SiO2)

Unidentified weathered rock fragments

Likely mixed silicate rocks; specific identification requires testing

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Raw selenite (gypsum)

Gypsum, CaSO₄·2H₂O; translucent variety selenite

Quartz crystal (likely clear quartz)

Quartz, silicon dioxide (SiO₂)

Mixed mineral and rock collection, including likely amethyst and assorted tumbled stones

Unidentified mixed specimens; visible purple quartz is likely amethyst (SiO₂)

Mixed rock and mineral collection

Multiple specimens; visible pieces may include quartz, calcite, agate/chalcedony, jasper, and dyed or coated materials

Limonite after Pyrite (Prophecy Stone or Ironstone Concretion)

Goethite/Limonite pseudomorph after Pyrite/Marcasite (FeO(OH)·nH2O)

Pyrite on Quartz

Iron Sulfide (FeS2) on Silicon Dioxide (SiO2)

Goethite pseudomorph after Pyrite

Goethite (FeO(OH)) pseudomorph after Pyrite (FeS2)

Quartz Vein in Sedimentary Matrix

Silicon Dioxide (SiO2) with host rock

Red Jasper (Quartzite)

Silicon Dioxide (SiO2) with iron oxide inclusions

Tumbled chalcedony (likely milky quartz)

Microcrystalline quartz, SiO₂; possibly pale agate or quartzite

Pyrite on Quartz matrix

Iron Disulfide (FeS2) on Silicon Dioxide (SiO2)

Small metallic-gold mineral fragment, possibly pyrite

Pyrite (FeS₂), if confirmed

Carved red coral bead (likely coral or coral-colored resin)

Corallium spp. (precious coral; calcium carbonate, CaCO₃)

Fossil shark tooth

Likely fossilized shark tooth, possibly *Carcharocles* or *Otodus* species

Quartz heart (likely milky/included quartz)

Quartz, silicon dioxide (SiO₂)

Amethyst and Hematite Bracelet

Amethyst (SiO2) and Hematite (Fe2O3)

Unidentified Rock Fragment

Unknown