They were of the slovenly English sort; and they consequently muddled it all, until Mr.Franklin took them in hand, and pointed out what they ought to see.
"Remark," says Mr.Franklin, "that the integrity of the Diamond, as a whole stone, is here artfully made dependent on the preservation from violence of the Colonel's life.

He is not satisfied with saying to the enemies he dreads, 'Kill me--and you will be no nearer to the Diamond than you are now; it is where you can't get at it--in the guarded strong-room of a bank.' He says instead, 'Kill me--and the Diamond will be the Diamond no longer; its identity will be destroyed.' What does that mean ?" Here I had (as I thought) a flash of the wonderful foreign brightness.
"I know," I said.

"It means lowering the value of the stone, and cheating the rogues in that way!" "Nothing of the sort," says Mr.Franklin.

"I have inquired about that.
The flawed Diamond, cut up, would actually fetch more than the Diamond as it now is; for this plain reason--that from four to six perfect brilliants might be cut from it, which would be, collectively, worth more money than the large--but imperfect single stone.

If robbery for the purpose of gain was at the bottom of the conspiracy, the Colonel's instructions absolutely made the Diamond better worth stealing.