The ice of this berg, although opaque and vascular, is true glacier
ice, having the fracture, lustre, and other external characters of
a nearly homogeneous growth. The iceberg is true ice, and is always
dreaded by ships. Indeed, though modified by climate, and especially by
the alternation of day and night, the polar glacier must be regarded as
strictly atmospheric in its increments, and not essentially differing
from the glacier of the Alps. The general appearance of a berg may be
compared to frosted silver; but when its fractures are very extensive,
the exposed faces have a very brilliant lustre. Nothing can be more
exquisite than a fresh, cleanly fractured berg surface: it reminds one
of the recent cleavage of sulphate of strontian--a resemblance more
striking from the slightly lazulitic tinge of each.--_U. S. Grinnel
Expedition in Search of Sir J. Franklin._