With
the malachite at Copper Queen Mine is a variety which has proved on
examination to consist of equal parts of carbonate of lime and
carbonate of copper. This is slightly harder than malachite, and the
name, calcomalachite, indicating its composition, has recently been
suggested for it. Like malachite, it admits of a fine polish and is
susceptible of similar uses.
A
beautiful compact chrysocolla, mixed with quartz, is found at the
Allouez Mine, Houghton, Lake Superior region. Some of the specimens
would furnish fine, rich, bluish-green gems half an inch square.
Specimens of chrysocolla from the Copper Queen Mine, Ariz., coated
with quartz and chalcedony, furnish beautiful gems when the polish on
the layer of quartz chalcedony is thin enough to allow the chrysocolla
to show through. In one case, these markings resembled a human head.
Aragonite
(carbonate of lime) or "satin spar," from near Dubuque, Iowa,
especially that from Rice's Cave, and in the remarkably fine forms
known as the " floss ferri " variety, from near Rapid City, Dak., would
admit of the same uses as common satin spar. The satin spar gypsum or
sulphate of lime, while made so extensively into ornaments and sold at
Niagara Falls and many tourists' resorts, is, almost without exception,
imported from Wales, though some few of the common white gypsum
ornaments sold at Niagara are cut from the gypsum found in the
vicinity. On Goat Island large masses of gypsum are found, and
occasionally even under the Falls, where the material for all the
ornaments sold there is supposed to be found. Beautiful selenite occurs
there, but no satin spar.
The
dark amber-colored and brown aragonite (California onyx) from
California is extensively used as an ornamental stone, but not as a gem
stone. Many thousands of dollars' worth are annually used by marble
workers and for decorative purposes.
In
the Luray and other American caves are found calcareous concretions
called cave pearls, which consist either of pieces of stalagmite worn
round by falling water or of similar pieces forming nuclei on which
successive layers of carbonate of lime have been deposited.
