He couldn't have
been paying a social call, because he wasn't there long enough. And what
business does he have with Guevara? I don't know, but I'll bet his
business is the reason we can't get Guevara to move."

"Possibly," Hartson Brant agreed. "I can see the reason for your
suspicions, but you lack proof of anything, Rick. What motive could
Connel have?"

"We hoped to find out at the shot station," Rick replied. "But we drew a
blank."

Dr. David Riddle came into the room and joined them. Before anyone could
speak, the geologist spotted the samples on the table and sucked in his
breath sharply.

"Where did these come from?" he demanded.

"Connel's third shot station," Rick replied. "Do you know what the stuff
is?"

Riddle sank into a chair and picked up one of the samples, testing it
between his fingers. "Yes," he said, "I do. I've seen it only once
before, in Africa. It occurs in what is known as a volcanic pipe,
actually an ancient channel that gets filled with the stuff for reasons
we do not know."

"A volcanic pipe," Hartson Brant said softly. "I'm beginning to see."

Rick wasn't. "But what is it?" he asked.

"The most valuable kind of ground in the world," Riddle said. "So far as
anyone knew up to now, such pipes have occurred only in Africa. The one
I saw was at Kimberley. The name came from there. This is kimberlite."

[Illustration]

Rick knew of only one kind of valuable that was associated with
Kimberley, and the thought was so staggering that he was almost afraid
to say it out loud. "You mean that this is the stuff diamonds are found
in?"

"Exactly," Riddle said.

Rick fished the handful of crystals from his pocket and stared at them
unbelievingly. "Then these," he said hoarsely, "must be diamonds!"

CHAPTER XI

Earthquake!

"Everything adds up," Rick Brant said grimly. "And it isn't a pretty
picture."

Hartson Brant agreed. "It certainly seems to add up, Rick. I suggest you
put those crystals in a safe place until we can find out for certain
whether or not there is real value there."

"Is there any doubt?" Scotty asked.

David Riddle answered, "Yes, Scotty. There are many grades of diamonds.
Until an expert takes a look at those Rick collected, we won't be sure
that they're of gem quality. He may have industrial grade diamonds, of
the type called bort."

"Connel may already have had an expert take a look," Weiss pointed out.

Rick examined the handful of crystals. It w