COQUINA, see under LIMESTONE
DIATOMITE, S-35. California.
White, fine grain, layered diatomaceous earth.
DOLOMITE, S-40. California. White,
medium to coarse grain.
DOLOMITE, S-40-A. Nevada.
Medium grain, crystalline, light gray, scattered
OTHER DOLOMITES IN MINERALS
FLINT, S-45. England. Dark gray to
black. Coatings of chalk on parts of some pieces.
GRAYWACKE, see under SANDSTONE
GYPSUM, S-50. Utah. Gray, impure
rock gypsum. Also called 'gyprock".
HEMATITE (Ironstone), S-55. Check for price and availability.
Alabama. So-called "oolitic" sedimentary iron
BANDED IRON FORMATION (Ironstone
or Iron Formation), S-55A.
Michigan. Classic iron
formation. Banded iron formation is an iron
rich sedimentary rock consisting
of alternating bands of iron-rich minerals (gray hematite
with minor magnetite here) and chert, quartz, or other fine
grained mineral (red jasper here).
This is from the Ironwood Iron Formation in the
Gogebic Range. Precambrian.
LIGNITE, see COAL
Coarse crystalline. White.
Stylolitic. Very fine grain.
LIMESTONE (OOLITE), S-60-B.
Idaho. Spectacular, light gray,light buff, loosely
consolidated 2-3 mm spherules.
SANDY BIOCLASTIC LIMESTONE, S-60-C.
Wyoming. Abundant fragments of
lamellibranch shells up to 2 inches in fine grain,
FOSSILIFEROUS LIMESTONE, S-60-D.
Texas. Fine grained, light buff, with many
fossils, especially gastropods and brachiopods.
ONCOLITIC LIMESTONE, S-60-E.
California. Gray, crystalline ovoids in fine
grain gray limestone with some brown
COQUINA LIMESTONE, S-60-F.
Florida. Buff, cemented shell fragments
averaging 5 mm.
COQUINA LIMESTONE, S-60-G.
California. Tightly consolidated average 1 to 5
mm shell fragments. SL Small pieces.
CALCAREOUS TUFA, S-60-H.
California. Fine grain. light buff, porous
Dark gray, fine to medium grain, with scattered 1-3 mm
and occasionally as large as 5 mm white to black calcite grains and cleavages.
LIMESTONE (MICRITE), S-60-J.
Texas or Nevada. Light gray to light brown or tan.
Very fine grain.
CHERTY DOLOMITIZED LIMESTONE,
Nevada. Gray, fine grain,
dolomitic with 5 mm to over 5 cm irregular