are frequently found in the jewelry stores of France, England,- and the United States,
occurs massive, globular, stalactiform, and in pseudo-morphous crystals
of carbonate of lime, and also in the form of petrified wood,
(wood-stone or agatized wood.) Its fracture is either conchoidal or
splintry; it is opaque or transparent on the edges; has a dull or
shining lustre;-deep gray, brown, red, yellow, or green, and rarely a
pure color. Often it has several colors in one and the same specimen,
such-as points, spots, and stripes. It scratches glass, and has a
specific gravity of 2.53 to 2.65.
is mostly found in the gangues of the older formation ; also in the old
red sandstones and alluvial formations, in Bohemia, Saxony, Sweden,
Siberia, Hungary, and a number of other places; in the old red
sandstone of Thuringia. I have traced one stem of the red agatized wood
eighteen feet in length and two feet in diameter. The price of
hornstone is very low ; it is used for snuff-boxes, seals, crosses,
mortars, and principally as knife and fork handles. It is now used by
silversmiths to mount butter and dessert knives and forks,' which are
imported from Germany in considerable quantities.
mineral was held in great estimation by the ancients, who received
their principal supplies from Egypt and other parts of Africa. In Home,
much use was made of it for cameos, many of which may yet be seen in
collections. The inhabitants of Iceland are likewise said to value it
very highly, and to attribute many medicinal properties to it.