a. A niobium-containing mineral used as raw material in the production of
ferroniobium. Osborne
b. A variety of tetrahedrite. Hey, 1
The carrying down by a precipitate of substances that are normally soluble
under the condition of precipitation. AGI
One of two commodities that must be produced to make a mine economic; both
influence output. A byproduct is produced in association with a main
product or with coproducts. See also:byproduct
Petrified excrement.
A trigonal mineral, Fe2 (SO4 )3 .9H2 O ;
dimorphous with paracoquimbite. Syn:white copperas
A detrital limestone composed wholly or chiefly of mechanically sorted
fossil debris that experienced abrasion and transport before reaching the
depositional site and that is weakly to moderately cemented, but not
completely indurated; esp. a porous light-colored limestone made up of
loosely aggregated shells and shell fragments, such as the relatively
recent deposits occurring in Florida and used for roadbeds and
construction. AGI
A limestone consisting of coarse, unsorted, and often unbroken shelly
materials that have accumulated in place without subsequent transportation
or agitation, and generally having a fine-grained matrix. It is
autochthonous, unlike the allochthonous coquina. AGI
An alteration product of uraninite partly changed to gummite.
Syn:uraninite
A general name for any of a large group of bottom-dwelling, sessile,
marine invertebrate organisms (polyps) that belong to the class Anthozoa
(phylum Coelenterata), are common in warm intertropical modern seas and
abundant in the fossil record in all periods later than the Cambrian,
produce external skeletons of calcium carbonate, and exist as solitary
individuals or grow in colonies. AGI
Said of a firm carbonate rock formed by an intergrowth of frame-building
corals and algae (esp. coralline algae). The material so formed is an
excellent sediment binder in a coral reef. AGI
A limestone consisting of the calcareous skeletons of corals, often
containing fragments of other organisms and often cemented by calcium
carbonate. AGI
a. Pertaining to, composed of, or having the form of a coral, as coralline
limestone.
b. Any organism that resembles a coral in forming a massive calcareous
skeleton or base, such as certain algae or stromatoporoids. AGI
Marine deposits formed around coral islands and coasts bordered by coral
reefs, containing abundant fragments of corals. Near the reefs the
particle sizes are relatively coarse and the deposit is described as coral
sand; farther out, the particles become gradually smaller until the
material is a coral mud. Holmes, 2
A curved, lamellar variety of liver-colored cinnabar from Idria, Austria.
Standard, 2
A well-cemented, rubbly limestone composed largely of broken and rolled
fragments of coral-reef deposits; e.g., the Coral Rag of the Jurassic,
used locally in Great Britain as a building stone. AGI
a. A coral-algal or coral-dominated organic reef; a mound or ridge of
in-place coral colonies and accumulated skeletal fragments, carbonate
sand, and limestone resulting from organic secretion of calcium carbonate
that lithifies colonies and sands. A coral reef is built up around a
potentially wave- and surf-resistant framework, esp. of coral colonies,
but often including many algae; the framework may constitute less than
half of the reef volume. Coral reefs occur today throughout the tropics,
wherever the temperature is suitable (generally above about 18 degrees C,
a winter minimum). AGI
b. A popular term for an organic reef of any type. AGI
Sand-size particles formed from coral fragments.
See also:coral mud and sand
The depth of the sea at which corals thrive. Fay
A plant group, which is now extinct, that includes the Coniferales (pines
and firs) and the Cycadales (cycads). The Cordaites were tall, slender
trees that often attained heights of 100 ft (30.5 m). For a considerable
height above the ground, the trunk was devoid of branches. The long,
straplike leaves now form matted masses among the Coal Measure fossil
plants. Nelson
A rubber belt consisting of spaced cotton duck cords embedded in the
rubber and protected at the top by a breaker strip with thick rubber
cover. The bottom of the belt contains one or two plies of heavy duct, to
give transverse strength. See also:nylon belt
An orthorhombic mineral, Mg2 Al4 Si5 O18 ;
Mohs hardness, 7 to 7.5; an accessory in peraluminous granite, schist, and
gneiss; a gem material called saphir d'eau, water sapphire, dichroite, and
iolite. Syn:polychroite