One of a series of borders of one or more secondary minerals around an
original crystal, representing the modification of a phenocryst due to the
corrosive action of its magma. CF:reaction rim
resorption border. AGI
The steady-state irreversible potential of a metal or alloy in a constant
corrosive environment. Schlain
The rate that a metal or alloy is removed because of corrosion. This may
be expressed in terms of loss in weight or loss of thickness in a given
period of time. (Corrosion rates in terms of thickness change refer to the
loss of metal from one side only.) Hunt
A pitted, irregular bedding surface found only in certain carbonate
sediments, characterized by a black manganiferous stain, and presumed to
result from cessation of lime deposition and from submarine solution or
resorption of some of the previously deposited materials.
Syn:corrosion zone
See:corrosion surface; corrosion border.
Where on a small scale, beds are much wrinkled, folded, or crumpled, they
are said to be corrugated. On a larger scale, they are said to be
contorted.
A fishing tool. Long
A trough with corrugations formed into the bottom to assist coal travel on
steep grades or under wet conditions. Jones, 1
In coal, that part of the axis of a vascular plant that surrounds the
central cylinder and is separated from the cylinder by the endodermis, and
limited on the outside by the epidermis.
A rock consisting of corundum and iron oxides. See also:emery rock
An iron-bearing variety of clinchlore.
A trigonal mineral, Al2 O3 ; hematite group; forms hexagonal
prisms with basal and rhombohedral parting; red (ruby), blue (sapphire),
green (oriental emerald), reddish-brown, white, or gray; defines 9 on the
Mohs hardness scale; in nepheline syenite pegmatites and placer deposits.
Emery is granular corundum mixed with magnetite and spinel. Synthetic
corundum made from bauxite together with other manufactured abrasives have
largely replaced natural materials.
Corundum showing a bluish, reddish, or yellowish reflection of light, or
lighter shade, than the stone itself. CF:asterism; star ruby;
star sapphire.
A monoclinic mineral, (Na,K,Ca,Mg)2 (V5+ ,V4+ )
8 O26 .6-10H2 O ; weakly radioactive; associated with
carnotite in Colorado and Utah; a source of vanadium.
Syn:blue-black ore
An orthorhombic mineral, Pb2 Bi2 S5 ; a source of
bismuth.
Contemporaneous deposition. AGI
The study of the origin, distribution, and abundance of elements in the
universe. AGI
a. A trench cut across the conjectured line of outcrop of a seam or
orebody to expose the full width. Nelson
b. The channel eroded by a flow of water to expose mineral deposits during
prospecting work. Nelson
c. In prospecting, to dig shallow pits or trenches designed to expose
bedrock. Etymol: Cornish. AGI
a. The removal of soil and subsoil by a rushing of water, to expose rock
formations in prospecting for reefs or lodes. CTD
b. Proving an ore deposit or vein by trenching across its outcrop at
approx. right angles. Weed, 2
c. Tracing a lode by pits sunk through overburden to underlying rock.
Pryor, 3
Corn. A pit sunk to bedrock in prospecting. Standard, 2
A special case of the boundary line, in ternary systems, along which one
of the two crystalline phases present reacts with the liquid, upon
decreasing the temperature, to form the other crystalline phase.
Syn:reaction curve; reaction line. AGI