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NATIVE FOSSILS.
CLASS III.
SPAR.
SPATUM.
A pure Foſſil; compoſed of Brittle Rhombs.
SPAR is known from Talc by its Want of Elaſticity;
from Selenite by its Want of Flexibility;
from Cryſtal by its Dullneſs, and by fermenting with Acids.
It is heavier than any of the three other pellucid Foſſils; and is known from all Bodies in the World (when pure enough to be ſeen through) by its doubling Lines laid under; and viewed through it.
This laſt Property has been ſuppofed peculiar to that Species of Spar called Iſland Cryſtal: And the greateſt Writers, Linnæus, Wallerius, Cronſtedt, and the long et cætera, have ſeparated
that
