A monoclinic mineral, MgCO3 .5H2 O ; forms small stalactites
that alter to nesquehonite in mines near Lansford, PA.
Enclosed light (candle or oil) carried by a mine worker. Hess
An orthorhombic mineral, (Ce,La,Nd)2 (CO3 )3 .8H (sub
2) ) ; further speciated according to its predominant rare-earth element;
in pegmatites and carbonate-rich sediments.
An iron curtain, stiffened by ribs of angle iron, suspended from trolley
wheels running on a rail parallel with and in front of a furnace to
protect the worker from the furnace heat. Fay
a. One coil of rope on the winding drum of the mine hoist.
Pryor, 3
b. Polishing cloth used in preparing polished mineral specimens by
abrasive grinding. Pryor, 3
c. A surface defect, appearing as a seam, caused by folding over hot
metal, fins, or sharp corners and then rolling or forging them into the
surface, but not welding them. ASM, 1
d. To dimension, smooth, or polish (as a metal surface or body) to a high
degree of refinement or accuracy. Webster 3rd
e. An imperfection; a fold in the surface of a glass article caused by
incorrect flow during forming. ASTM
f. A tool used for polishing glass. ASTM
g. A rotating disk of soft metal or wood, used to hold polishing powder
for cutting or polishing gems or metal.
Impure sandy green limestone with shaly partings in the Middle Purbeck
beds, Swanage, U.K. Also spelled leaper; leper.
a. An artificer who cuts, polishes, or engraves gems or precious stones.
b. Person who is skilled in the nature and kind of gems or precious
stones; a connoisseur of lapidary work.
Pyroclastics that may be either essential, accessory, or accidental in
origin, of a size range that has been variously defined within the limits
of 2 mm and 64 mm. The fragments may be either solidified or still viscous
when they land (though some classifications restrict the term to the
former); thus there is no characteristic shape. An individual fragment is
called a lapillus. CF:cinder
Having the form of small stones.
a. A lazurite-bearing rock; contains lazurite or hauyne (possibly
zeolitized), diopside, edenitic amphibole (koksharovite), muscovite,
calcite, and pyrite; occurs in various shades of blue; possibly the
original sapphire of the ancients; Syn:azure; lazuli.
b. Gem-quality lazurite. (Not lazulite.)
c. An ultramarine-colored serpentine in India. See also:ultramarine
Lapis lazuli (lazurite) containing prominent patches of calcite.
See also:Chilean lapis; lazurite.
Miniature belt conveyor, on which small ore particles move singly past a
Geiger-Mueller tube that is set to operate a sorting device. This removes
from the passing stream each particle of radioactive ore that reaches the
required intensity, therefore sorting out the valuable material.
Pryor, 3
a. Overlapped and fitted together. Nichols, 1
b. The act of polishing or grinding on a lap.
A time of deformation, typically recorded in the eastern Rocky Mountains
of the United States, whose several phases extended from late Cretaceous
until the end of the Paleocene. It is named for the Laramie Formation of
Wyoming and Colorado, probably a synorogenic deposit. AGI
See:Laramide orogeny
See:laurdalite
A monoclinic mineral, (NH4 )B5 O6 (OH)4 .
a. White hydrated silica, probably a variety of opal; occurring in clay in
central Russia.
b. Massive talc. Syn:steatite; agalmatolite.
c. A massive variety of muscovite and/or pyrophyllite.
See also:pagodite
An oil produced from animal fats. This oil is an efficient lubricant for
use on metal-cutting tools. Crispin
Massive talc; steatite.
A kind of soft stone found in China. See also:steatite; agalmatolite.
Fay