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lucianite

An expansive clay of the smectite(?) group at Santa Lucia, near Mexico,
D.F.

lucid attrite

Variety of attritus that is transparent in thin section. Tomkeieff

lucinite

A variety of variscite from Lucin, UT.

Luckiesh-Moss visibility meter

This instrument has been used over a wide range of lighting applications.
It consists of a pair of similar photographic gradient filters, which
increase in density as they are rotated together before the eyes. The
filters therefore reduce the apparent brightness of the observed field and
at the same time lower the contrast between the object of view and its
background. Roberts, 2

luckite

A manganoan variety of melanterite at the Lucky Boy Mine, Salt Lake
County, UT.

lucky stone

See:staurolite

Lueders line

Surface markings that result from strain. Sometimes called Hartmann lines;
Piobert lines; stretcher strains. See also:slip line

ludlamite

A monoclinic mineral, (Fe,Mg,Mn)3 (PO4 )2 .4H2
O ; green; in small tabular crystals at Truro, Cornwall, U.K.
Syn:lehrnerite

ludwigite

An orthorhombic mineral, Mg2 FeBO5 ; forms a series with
vosenite; forms finely fibrous masses. Includes magnesioludwigite,
ferroludwigite. Syn:collbranite

lue

Prov. Eng. To sift; a miner's term. Standard, 2

lueneburgite

Alternate spelling of lueneburgite.

lueshite

A monoclinic mineral, NaNbO3 ; perovskite group; pseudocubic;
dimorphous with natroniobite. Syn:igdloite

luffing cableway mast

A cableway tower hinged at the base and sustained by adjustable guys so
that its inclination can be varied. Hammond

lug

a. A replaceable cutting member on an expansion reamer. Long
b. One of a set of cutting lugs used to cut off a length of casing in a
borehole at any desired point below the collar of the hole. Syn:jaw

lug down

To slow down an engine by increasing its load beyond its capacity.
Nichols, 1

lugeon test

Single-hole in situ test of formation permeability performed by measuring
the volume of water taken in a section of test hole when the interval is
pressurized at 10 bars (150 psi). Used primarily in variably permeable
formations under evaluation for grouting. Houlsby

Luhrig vanner

Vanning machine with side feed and end shake--a hybrid between the true
vanner and the shaking table. Pryor, 3

lumachelle

a. A compact, dark-gray or dark-brown limestone or marble, composed
chiefly of fossil mollusk shells, and characterized by a brilliant
iridescence or chatoyant reflection from within. Syn:fire marble
AGI
b. Any accumulation of shells (esp. oysters) in stratified rocks. Etymol:
French, coquina, oyster bed, from Italian lumachella, little snail.
AGI

lumber

Timber that has been sawed into boards, planks, staves, or other pieces of
comparatively small dimensions. In mines, timber is used in the
construction of coal chutes, mine cars, mine doors, forms for concrete
structures, surface buildings, and for many other purposes.
Jones, 2

lumber scale

A graduated measuring scale for determining the number of board feet in
rough-sawed lumber. Crispin

luminance

A measure of surface brightness that is expressed as luminous flux per
unit solid angle per unit projected area. ASM, 1