Lanc. A dark-brown powdery substance, consisting of silica, alumina, and
iron; found in iron mines.
A mud formed in lagoons, sounds, or bays, in which there is poor
circulation or weak tides. The color is black because of iron sulfides and
organic matter. AGI
See:wad; bog manganese.
Precious opal with play of color (commonly red or green) displayed against
a dark gray (rarely black) body color; e.g., the fine Australian blue opal
with flame-colored flashes.
a. Eng. Partly decomposed pyrite containing copper. Fay
b. In uranium mining, the term may mean ore containing a high proportion
of pitchblende, uraninite, coffinite, or vanoxite.
c. Cumb. A variety of hematite in hard pieces, some kidney shaped,
reaching the size of one's hand, in a moderately soft, dark-red, brown, or
nearly black mass of smit clay and manganese oxide, the whole having a
most confused appearance.
See:pyrolusite
Lampblack obtained by burning common coal tar. Fay
A deflagrating or low-explosive granular compound of sulfur, charcoal, and
an alkali nitrate, usually potassium or sodium nitrate.
Syn:black gunpowder
In fluidization roasting (fluosolids process), the conversion of iron
sulfide to magnetite. Pryor, 3
A precipitated black magnetic iron oxide. Used mainly in plate printing
inks and in paints, but has small abrasive applications.
See also:black magnetic rouge
a. An alluvial or beach sand consisting predominantly of grains of heavy,
dark minerals or rocks (e.g., magnetite, rutile, garnet, or basaltic
glass), concentrated chiefly by wave, current, or surf action. It may
yield valuable minerals. See also:beach placer
b. An asphaltic sand. AGI
a. A dark, thinly laminated carbonaceous shale, exceptionally rich in
organic matter (5% or more carbon content) and sulfide (esp. iron sulfide,
usually pyrite), and often containing unusual concentrations of certain
trace elements (U, V, Cu, Ni). It is formed by partial anaerobic decay of
buried organic matter in a quiet-water, reducing environment (such as in a
stagnant marine basin) characterized by restricted circulation and very
slow deposition of clastic material. Fossil organisms are preserved as a
graphitic or carbonaceous film or as pyrite replacements.
Syn:biopelite
b. Usually a very thin-bedded shale, rich in sulfides (esp. pyrite, which
may have replaced fossils) and rich in organic material, deposited under
barred basin conditions causing anaerobic accumulation. AGI
c. Generally, a fine-grained, finely laminated carbonaceous shale,
sometimes canneloid, often found as a roof to a coal, or in place of a
coal, resting on a fire clay. Syn:black metal
See:stephanite
A hydrothermal vent at the crest of an oceanic ridge; e.g., the East
Pacific Rise at the mouth of the Gulf of California. Waters blackened by
sulfide precipitates jet out at 1 to 5 m/s at temperatures of at least 350
degrees C. The term refers to uprushing black turbulent suspension.
CF:white smoker
See:nagyagite
a. A rare gray metallic mineral, a sulfotelluride of gold and lead with
some antimony. CTD
b. See:nagyagite
Eng. Dressed tin ore ready to be smelted; from Cornwall.
See also:cassiterite
An early name for several minerals, including graphite and the softer
manganese oxides.
A positive displacement pump in which compressed air is forced down an
input column to squeeze a water-filled bladder, thereby forcing water up a
discharge column to the ground surface. The bladder refills by gravity
flow at the end of each lifting cycle, because the bladder unit is below
the static water lever. See:positive displacement pump.
a. The shape of a solid, as one in which the ratios of breadth to length
and thickness to breadth are each less than 2:3.
b. Having the appearance of blades, e.g., flat crystals strongly elongated
in one direction.
Decidedly elongated and flattened; descriptive of some minerals.
Fay