-
Because obsidian is
metastable at the Earth's
surface (over time the gl****
devitrifies,
becoming fine-grained
mineral crystals),
obsidian older than Miocene...
- one face may be
exposed to
conditions causing the
fibers to
partially devitrify.
Depending on the
chemical composition of the gl****y
fiber and the time...
-
temperature just
insufficient to
cause fusion. In this way, the crystalline,
devitrified material,
known as Réaumur's gl****
porcelain is produced.
Although generally...
-
processes in
igneous rocks. It is
called 'graphic'
because the
exsolved or
devitrified minerals form
lines and
shapes which are
reminiscent of writing. Graphic...
-
variable amounts of
olivine and
augite in a gl****y matrix; the gl**** may be
devitrified. It was
originally described and
named by J. W.
Gregory in 1900 for the...
- and the gl**** plies. A
sacrificial outer layer that
cracks rather than
devitrifies is the
first failsafe.
Circular bullseyes,
linear cracks,
crack chips...
-
bentonite is more common. In
stratigraphy and tephrochronology,
completely devitrified (weathered
volcanic gl****) ash-fall beds are
sometimes also referred...
-
calcium bentonite. In
stratigraphy and tephrochronology,
completely devitrified (weathered
volcanic gl****) ash-fall beds are
commonly referred to as...
-
pigments that were
originally blue are now green: the blue frit can "
devitrify" so that the "copper
wollastonite predominates over the
lesser component...
- due to the
effect of
pressure and temperature. The
pyroclastic flows devitrify and weld
together and
spread during the
volcanic action,
forming a kind...
