Man Made Composite (Lithified Equivalent Of Sedimentary)

Weathered carbonate rock, possibly fossiliferous limestone

Calcite-rich limestone (CaCO₃), tentative identification

Iron-rich sandstone or weathered ironstone

Ferruginous sandstone, commonly quartz (SiO₂) cemented or stained by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

Banded sandstone or quartzite fragment

Quartz-rich sandstone; possibly weakly metamorphosed quartzite

Likely calcite-bearing limestone

Calcite (CaCO₃), probably in a porous limestone fragment

Rounded iron-rich river pebble

Likely ferruginous sandstone or ironstone; exact identification requires testing

Quartz-rich sandstone or quartzite fragment

Quartz sandstone; possibly weakly metamorphosed quartzite (SiO₂-dominant)

Polished gray pebble

Likely quartz-rich chert or fine-grained quartzite; exact identification is uncertain from the photograph

Chert

Chert (Microcrystalline Quartz)

Chalk

Calcium Carbonate (CaCO3)

Rounded quartz-rich river pebble

Likely quartzite or weathered sandstone; exact identification requires testing

Likely weathered iron-rich sandstone or laterite

Ferruginous sandstone; predominantly quartz (SiO₂) cemented or stained by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

Fossiliferous Limestone

Fossiliferous Calcite (CaCO3)

Fossil Coral

Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)

Fossiliferous Limestone

Calcium Carbonate - CaCO3

Weathered sandstone or iron-rich sedimentary rock

Likely ferruginous sandstone; exact identification is uncertain from the photograph

Fossiliferous limestone pebble

Bioclastic limestone, commonly calcitic (CaCO₃)

Fossilized stromatolite or laminated microbial mat

Layered carbonate/chert fossil; exact taxon indeterminate from the image

Fossilized Brachiopod

Phylum Brachiopoda (likely Order Spiriferida or Orthida)

Weathered iron-rich sandstone or laterite

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

Fossiliferous Limestone

Sedimentary Calcium Carbonate (CaCO3)

Flagstone paving (likely sandstone or limestone)

Clastic sandstone or carbonate limestone; exact identification requires testing

Blue chalcedony cabochon (probable)

Chalcedony, a cryptocrystalline variety of quartz; silicon dioxide, SiO₂

Colorless faceted gemstone, likely glass or cubic zirconia

Uncertain; possible cubic zirconia (ZrO₂) or quartz (SiO₂), but the image may show a man-made simulant

Colorless faceted quartz-like gemstone

Likely quartz (SiO₂), though the appearance may also indicate man-made glass or cubic zirconia

Fossiliferous Limestone with Coral Imprint

Fossiliferous Limestone (CaCO3)

Fossil Brachiopod or Mollusk Cast

Phylum Brachiopoda / Mollusca internal mold

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Fossiliferous limestone pebble

Calcite-rich limestone (primarily CaCO₃), with possible fossil or fossil-fragment patterns

Fossilized Ripple Marks or Stromatolite

Sedimentary ripple mark imprint / Biosedimentary structure

Weathered limestone or dolostone

Calcite-rich limestone (CaCO₃), possibly dolomite-bearing

Rounded quartz-rich sandstone pebble

Quartz arenite (sandstone), composition mainly SiO₂ with minor feldspar, mica, and iron-oxide cement

Conglomeratic sandstone or breccia specimen

Quartz-rich clastic sedimentary rock; likely sandstone with pebble-sized quartz, feldspar, and lithic clasts

Rounded weathered pebble, likely chert or fine-grained quartzite

Microcrystalline quartz (SiO₂), probable chert; quartzite is an alternative

Likely weathered sandstone or iron-stained sedimentary fragment

Quartz-rich sandstone; exact identification requires testing

Weathered quartz-rich sandstone or quartzite

Quartzite (predominantly SiO₂), possibly strongly cemented sandstone

Crinoid Fossil Fragment

Crinoidea (echinoderm fossil embedded in limestone/matrix)

Fossil-bearing limestone or calcareous mudstone pebble

Micritic limestone, primarily calcite (CaCO₃), with possible fossil or iron-oxide vein features

Fossiliferous Limestone

Biomicrite / Fossiliferous Limestone (CaCO3)

Brain Coral Fossil

Family Mussidae or Merulinidae (Order Scleractinia)

Banded sandstone pebble

Quartz-rich lithic sandstone; exact provenance and composition require testing

Weathered sandstone pebble

Sandstone, likely quartz-rich (arkose or quartz arenite)