d red diamonds are the most valuable of
stones. This diamond is a blue one--not very large, but a particularly
fine stone."

"Of course the necklace is well-known to jewel experts?"

"As well-known as any piece of jewellery in Europe. Some of the pearls
in it are hundreds of years old. It would be almost impossible for the
thief to dispose of the necklace."

"It might be taken to pieces," suggested Colwyn.

"In order to hide its identity? Well, yes, but the selling value would
be greatly reduced. The pearls have been strung."

"What about the diamond? Could not that be sold by the thief without
risk of discovery?"

"Only by sending it to Amsterdam to get it cut into two or three smaller
stones, so as to lessen the risk of detection. The Heredith blue diamond
is known to many connoisseurs. It is cut in an unusual form--a kind of
irregular rosette, in order to display its fire and optical properties
to the best advantage. If it were cut it would lose a great deal of its
value. The money value of one large diamond of first quality is very
much greater than the same stone cut into three. But it would be
difficult to sell the diamond in its present form. The chances are that
it would be recognized in Hatton Garden--if it were offered for sale
there."

"But if the diamond fell into the hands of somebody with a knowledge of
precious stones he might keep it close for a while and then dispose of
it abroad--in America, for instance," returned Colwyn. "That trick has
been performed with better-known stones than the Heredith diamond. In
fact, it strikes me as possible to sell the whole necklace that way. The
disposal of the necklace depends largely upon who stole it--upon whether
it has fallen into experienced or inexperienced hands. There are jewel
dealers who ask no awkward questions if they can get things at their own
price."

"Quite so," assented Musard, casting a quick glance at his companion's
face. "It would be a risk, though--the thief might pick the wrong man. I
can give you the addresses of two or three men in Hatton Garden who
should be able to tell you if the necklace has been offered there. They
know everything that is going on in the trade."

"I shall be glad to have them."

Musard scribbled several names and addresses on a leaf of his
pocket-book, tore it out, and handed it to the detective.

"There is a curious coincidence about the loss of this, necklace," he
remarked casually, as he rose to go. "It i