a. The main stream of an intermontane valley, which flows along the lowest
part of the valley and parallel to its long dimension, in
contradistinction to the streams that flow down the mountains on either
side.
b. A stream that follows the axis of an anticline or a syncline.
The intersection of the axial plane of a fold with the surface of the
Earth or any other specified surface.
a. The mineral group ferroaxinite, magnesioaxinite, manganaxinite, and
tinzenite.
b. Triclinic borosilicates with the formula A3 Al2 BSi (sub
4) O15 (OH) where A = (Ca,Fe,Mg,Mn). Syn:glass schorl
A term proposed by Zirkel for a variety of elongated spherulite in which
there is an aggregation of minute acicular crystals arranged at right
angles to a central axis rather than from a point.
a. The central or dominating region of a mountain chain, or the line that
follows the crest of a range and thus indicates the most conspicuous part
of the uplift.
b. The centerline of a tunnel. Nichols, 1
c. Intersection of the axial plane of a fold with a particular bed; axial
line.
d. A straight line about which a body or a three-dimensional figure
rotates or may be supposed to rotate; a straight line with respect to
which a body, figure, or system of points is either radially or
bilaterally symmetrical. Webster 3rd
e. In crystallography, one of the imaginary lines in a crystal that are
used as coordinate of axes of reference in determining the positions and
symbols of the crystal planes. CF:crystallographic axes;
coordinate system.
f. Often used synonymously with anticlinal; thus, the Brady's bend axis
for Brady's bend anticlinal. See also:anticlinal axis; synclinal axis.
g. The trace of the axial surface of a fold on the fold profile plane
(obsolete).
h. A line that follows the trend of large landforms, e.g., the crest of a
ridge or mountain range, or the bottom or trough of a depression. Plural:
axes.
For many transducers, the three-dimensional directivity is such that it
may be represented by the surface generated by rotating a two-dimensional
directivity pattern about the axis corresponding to the reference bearing
of the transducer. This axis may then be described as an axis of acoustic
symmetry or as the acoustic axis. Hy
An imaginary line in a crystal, crystal structure, or crystal lattice,
about which it may be rotated to an identical configuration. If identity
occurs once during a complete rotation of 360 degrees , the axis is a
monad, twice a diad, thrice a triad, four times a tetrad, or six times a
hexad. Syn:symmetry axis
A method of projection which has the advantage of containing a true plan,
and can therefore be set up from drawings already in existence for other
purposes. The plan is turned through 45 degrees , vertical lines being
drawn from the angles on the plan to show the elevations.
See also:oblique projection; isometric projection. Hammond
In crystallography, having cleavage perpendicular to an axis; said of
minerals. Standard, 2
A variety of nephrite jade. Also spelled axestone.
Direction of a horizontal line as measured on an imaginary horizontal
circle, the horizontal direction reckoned clockwise from the meridian
plane of the observer, expressed as the angular distance between the
vertical plane passing through the point of observation and the poles of
the Earth and the vertical plane passing through the observer and the
object under observation. In the basic control surveys of the United
States, azimuths are measured clockwise from south, a practice not
followed in all countries. CF:bearing
A variety of altered zircon. See:zircon
a. A greenish variety of smithsonite.
b. A green variety of turquoise.
Small cloudy sapphires occuring with diamonds in Brazil.
See:azurlite
See:lapis lazuli; lazurite.
See:azurmalachite
See:sapphire quartz
See:azurite; lazulite.
A term applied to lapis lazuli (lazurite) and to other blue minerals such
as lazulite and azurite.
a. A monoclinic mineral, 2[Cu3 (OH)2 (CO3 )2 ];
forms vitreous azure crystals; a supergene mineral in oxidized parts of
copper deposits associated with malachite; an ore of copper.
Syn:azure spar; chessylite; blue copper; blue copper ore;
blue malachite.
b. A compact semiprecious stone derived from compact azurite and used as a
decorator material.
c. A trade name for a sky-blue gem variety of smithsonite.