Glass: A Pocket Dictionary Of Terms Commonly Used - Corning ...

30
of unsuccessful annealing or accidental heating to a
high temperature. it is not caused by chemical reaction
between glass and its environment, which is known as
weathering.
Diamond air trap: Decoration consisting of bubbles of
air trapped in the glass in a diamond-shaped pattern.
This is achieved by blowing a gather of glass into a
mold with projections of the desired design, withdrawing
it, and covering it with a second gather, which traps
pockets of air in the indentations. This technique was
patented by W. H., b. & J. richardson of England in 1857.
Diamond-point engraving: The technique of decorating
glass by scratching the surface with a diamond.
Diamond-tipped tools may have been used by the
ancient romans and in the medieval islamic world, but
they were popularized by the venetians in the 16th cen-
Diamond-point engraved plate. France or Low Countries,
about 1630–1640. D. 48.4 cm.