of the Paris Exposition, 195 
U1 : 
dark green, chrysolite-green, topaz-yellow, hyacinth-red, pink, 
Cinnamon-brown, bluish-black with the luster of steel, and 
black with a lavender shade. A peculiar steel-like and graphite- 
like luster of the gem was well shown ina tiara and necklace 
formed of about forty stones, ranging from one-quarter of an 
inch to five-eighths of an inch in diameter, but not, however, 
wholly free from flaws, : 
In connection with the very interesting exhibition by Mr. 
Coster of Amsterdam, of the art of cutting and polishing dia- 
monds, there was a remarkably fine display of the rough stones 
from all the principal diamond-producing localities. All the 
varieties of crystalline form and of color were shown, together 
with the minerals and rolled pebbles usually found associated 
with the diamonds in the deposits. Inasuite of highly colored 
diamonds in this collection, there were two remarkable stones. 
One of 29 carats weight (about 92 grains), a pear-shaped bril- 
liant, about three-quarters of an inch long, has the property of 
acquiring a rose-pink color, on being strongly eated. This 
color is retained in the dark after cooling, but if the gem is ex- 
posed to the light, the color soon vanishes. The experiment 
as been repeatedly performed with like results, Another stone 
with a beautiful bluish-black color by reflected light, ap’ sare 
perfectly opaque when held between the eye and the light, 
Owing, probably, to the total reflection of the light from the 
facets of the stone. : 
The collection contained masses of the crude black variety. 
known as “carbon,” valuable for its powder. oe shaped 
fragments of this are found with the diamonds of and 
5, 
