Sedimentary Rock Identification

Does the rock contain visible sediment particles?

  1. Yes...go to 2.
  2. No...go to 1.
  1. No visible sediment particles.
    Rock Color Description Rock Name
    Light color light pink, white or gray color, reacts with acid, may contain oceanic fossils, made up mostly of calcite from ocean water. Limestone
    light gray, tan or brown color, chalky feel, made up of silt (grain size between clay and sand). Siltstone
    Dark color black, usually shiny, smudges fingers, low density, made up of plant remains. Coal
    shades of gray or red, usually layered, breaks along flat surfaces, made of mud or clay. Shale/mudstone
  2. Visible sediment particles. Does the rock contain shells or pieces of shell?
    1. Yes...go to 3.
    2. No...go to 4.
  3. Visible sediment particles with shells
    Description Rock Name
    Light in color, made up almost entirely of shells or pieces of shell cemented together. Coquina
  4. Visible sediment particles with no shells
    Sediment Particle Size Description Rock Name
    Mixed - both large and small. multicolored, made up of large angular rock fragments cemented together. Breccia
    multicolored, made up of large rounded rock fragments cemented together with smaller sediments. Conglomerate
    Mostly the same size. maroon color, made up mostly of sand-size particles with some pebbles cemented together, particles are mostly quartz and orthoclase. Arkose
    light color (usually white to tan), made up of sand-size particles cemented together, particles are mostly quartz. Sandstone