See:liroconite
a. A soft, earthy, medium-brown coallike substance associated with
lignitic outcrops in North Dakota. It is a naturally oxidized form of
lignite with variations in color and properties depending upon the extent
of weathering. Usually, the material occurs at shallow depths, overlying
or grading into the harder and more compact lignite. Of little value as a
fuel, it has been used in oil-drilling muds, in water treatment, and in
certain wood stains. It is frequently referred to as "slack" because of
its texture; however, the term leonardite is finding common usage.
b. A weathering product of subbituminous coal or lignite, rich in humic
and fulvic acids and soluble in alkaline water. It is a byproduct of
mining near-surface coal seams, and is used as a soil conditioner,
additive to drilling mud, and binder for taconite iron ore (Fowkes &
Frost, 1960). Not to be confused with leonhardite or leonhardtite.
AGI
A combustible gases detector developed in 1902. A form of Wheatstone
bridge is used and changes in electrical resistance due to temperature
differences are measured. The combustible gases/air sample flows over one
set of wires and the gas burns catalytically while the other wires do not
come into contact with the sample. Nelson
A partially dehydrated variety of laumontite. (Not leonhardtite.)
See:starkeyite
A monoclinic mineral, K2 Mg(SO4 )2 .4H2 O ; in
marine evaporite deposits. Syn:magnesium leonite
A variety of quartz porphyry containing small phenocrysts of quartz in a
microgranitic groundmass of quartz, orthoclase, albite, and mica. The rock
has a characteristically spotted or streaked appearance due to staining by
hydroxides of iron and manganese.
a. Can. Pegmatitic rocks associated with the apatite veins of Ontario and
Quebec.
b. Syenite gneiss consisting of ellipsoidal lumps measuring several inches
across and separated by material that is mainly greenish pyroxene. The
rock may be slightly schistose.
Dolomite full of worm castings set in a gray matrix and containing chert
nodules, near the base of the Upper Cambrian, Scotland.
A furnace for roasting mercury ores in a batch process, differing from the
Bustamente furnace in having a series of brick condensing chambers.
Fay
See:sylvite
Pertaining to a flaky schistosity caused by an abundance of minerals like
micas and chlorites with a general parallel arrangement.
An orthorhombic mineral, 4[gamma-FeO(OH)] ; polymorphous with akaganeite,
feroxyhyte, and goethite; yellow to orange-red; the weathering product of
iron-bearing minerals; forms the pigment brown ocher; such iron
oxyhydroxides constitute the rock limonite.
a. A monoclinic, trigonal, or orthorhombic mineral; 1, 2, or 3[K2
Li4 Al2 (Si8 O20 (OH)4 ] ; mica group;
forms a series with muscovite; perfect basal cleavage; pink to purple; in
lithium-rich granite pegmatites; a source of lithium. Syn:lithia mica;
lithionite.
b. A group name for lithium-rich micas.
A black ferrian variety of biotite.
A variety of phengite, a siliceous variety of muscovite.
See:anorthite
Said of a hydrothermal mineral deposit formed at temperature and depth
conditions intermediate between mesothermal and epithermal; also, said of
that environment. CF:hypothermal deposit; xenothermal; telethermal.
AGI
A fissile or schistose variety of hornfels containing mica, quartz, and
feldspar, with or without accessories, such as andalusite and cordierite.
The term was originated by Cordier in 1868. CF:cornubianite
AGI
A mathematical method based on a block model of an orebody used for
determining the most profitable optimum shape for an open pit.
See:vermiculite