latter substance. This mineral is found in the serpentine of Silesia;
also, in Siberia, and in the United States (in New Hampshire).
Chrysoprase is used in jewelry and for various ornamental purposes, such as breastpins, rings, bracelets, necklaces, seals, &c. ; and the larger masses are used for snuff-boxes, cane-heads, table-plates, &c. The
cutting is pretty difficult, and the greatest care is required for
finishing the same with facets, as it is easily fissured ; it is done
on tin or lead plates with' emery, keeping the first constantly wet
with water ; it is polished on a tin plate with rotten-stone, but the
lapidary has always to be cautious not to let it become hot, as it
easily splinters, and grows opaque and gray. The usual cut is the table
or cabochon, with facets on the border ; in setting, a foil of green
satin is often used for a back, but when pure and of good color, it is
mounted à jour. Inferior specimens are painted on the back with a mixture of verdigris, white lead, and gum mastic, or with sap-green.
Chrysoprase loses its color by wearing ; heat and sunlight likewise
cause it to fade, and render it dark and cloudy ; but the color may be
restored by keeping it in a wet or moist place, such as a cellar, in
wet cotton or sponge, or even by dipping it in a solution of nitrate of
nickel, which serves likewise to improve the inferior qualities.
Very fine imitations in paste may be made by mixing