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Glossary of Rock and Mineral Terms - X,
Y, Z
A | B
| C | D
| E | F
| G | H
| I | J
| K | L
| M | N
| O | P
| Q | R
| S | T
| U | V
| W | X
| Y | Z
- xenolith
- A preexisting rock embedded in a newer igneous rock. Xenoliths are
formed when a rising magma incorporates the preexisting rock. If the
preexisting rock does not melt, it will not be assimilated into the magma and
will therefore remain distinct from the new igneous rock that surrounds it.
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- xray
- Electromagnetic radiation that has a very short wavelength, emitted from a
substance when it is attacked by a line of electrons in a vacuum. Machines are
able to produce this, and they are known as x-ray machines. They are useful in
geology and mineralogy for the study of the chemical constituents of rocks and
minerals.
- x-ray diffraction
- The scattering of X rays passed through a mineral sample so as to form a
pattern peculiar to the given mineral.
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- yield point
- The maximum stress that a given rock can withstand without becoming
permanently deformed.
zeolite group
- Group of around 30 minerals that are related in structure, habits, and
occurrence. The zeolites are hydrous aluminum silicates that contain sodium or
calcium, which can replace one another. These minerals are usually found in
zeolite deposits, which are of igneous origin. Individual member is a zeolite.
- zoning
- The distinction of particular rock material from surrounding rock material.
- zone of ablation
- The part of a glacier in which there is greater overall loss than
gain in volume. A zone of ablation can be identified in the summer by an
expanse of bare ice. See also zone of accumulation.
- zone of accumulation
- The part of a glacier in which there is greater overall gain than
loss in volume. A zone of accumulation can be identified by a blanket of snow
that survives summer melting. See also zone of ablation.
- zone of aeration
- A region below the Earth's surface that is marked by the presence of both
water and air in the pores of rocks and soil. Also called aeration zone.
- zone of saturation
- A region that lies below the zone of aeration and is marked by the
presence of water and the absence of air in the pores of rocks and soil.
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