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
pore spaces.

OTHER DOLOMITES IN MINERALS SECTION

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
ore.  OOS.

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

LIMESTONE, S-60. California.
Coarse crystalline. White.

LIMESTONE, S-60-A. California.
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,
sand-rich carbonate.

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
mottling. Check.

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
sinter.  Check.

LIMESTONE, S-60-I. California.
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,
S-60-K. Nevada. Gray, fine grain,
dolomitic with 5 mm to over 5 cm irregular
chert nodules.