22 
Frequently pearls have an opaque appearance and seem 
to be worthless, but upon the removal of their outer layer 
are found to be clear and iridescent. This outer layer may 
be removed by dipping them ina weak solution of acid, 
which dissolves the opaque coating, or it may be peeled 
with a knife; although sometimes the pearl is not of the 
same material throughout and cannot be. 
That conchologists make so few references to pearls is 
probably accounted ‘for by the fact that the pearls are con- 
tained in old, distorted and diseased shells, which are not 
so desirable for collections as the finer specimens. Col- 
lectors who have opened many thousands of Unios have 
never observed a pearl of value. 
Large and valuable Unio pearls have been obtained in 
New Jersey. In 1857a pearl of fie lustre, weighing 93 
grains, was found at Notch Brook, near Paterson. It be- 
came known as the ‘‘ Queen Pearl,’’ and was sold by Tif- 
fany & Co. to the Empress Eugenie of France for $2,500. 
It is to-day worth more than four times that amount, and 
is finer than any pearl shown at the 1893 World’s Colum- 
bian Exposition. The news of this sale created the first 
great pearl excitement that led to the search for pearls 
which spread westward throughout the country. The 
Unios at Notch Brook and elsewhere were gathered by 
millions and destroyed, often with little or no result. A 
large round pearl weighing 400 grains, which would doubt- 
less have been the finest pearl of modern times, was ruined 
by boiling open the shell. 
Within one year pearls were sent to the New York mar- 
ket from nearly every State. In 1857 fully $15,000 worth; 
in 1858 about $2,000; in 1859 about $2,000; in 1860 about 
$1,500 ; in 1868, when there was a slight revival of interest, 
and since then, many Little Miami River pearls have been 
found. Since 1860, pearls have come from a comparatively 
new district, the supply from which is apparently on the 
increase. At first few were found, or rather few were 
