“Has the stone been

set yet?”

I was a very young diamond marker (designing the best use of the rough). I was sixteen years old. (after countless discussions of where to cleave this piece of rough to best effect)

I was given the Cullinan to mark - there was no one else.

Exactly according to the grain or growth lines I drew a line. Once the line was on the stone we concluded that the black imperfection, in the diamond jargon called ‘a fly’, was just under the first line. There are two ways to correct this; wipe the stone clean and do it all over again or more practically, draw a second line about one millimetre apart. Now the impurity was exactly in the middle of the two lines and that’s were the first groove would be made.

;My brother gave the marked stone to the older cleavers to set the stone in the cleaving stick, I have to admit that I was a little disappointed because I sort of counted on the honour of doing that job myself.

But youth is indifferent and in the workshop I worked on the cleaving blades and also had a beautiful Flobet .22 rifle and I really enjoyed shooting with her.

It must have been a good hour or so later when someone came to see where I was hanging out. “Has the stone been set yet” I asked.

“No they haven’t managed it yet”.

I reloaded my rifle and pulled the trigger, bulls eye! “Nice shot don’t you think”


Joseph carefully grooving the Cullinan. Above, sticks with shellac tops ready for holding the Cullinan.

“Shouldn’t you go and have a look in the cleaving workshop?”

“Nah” I said, “If they need me They know where to find me”

“Don’t be so bloody stubborn and go and have a look” was the reply.

And so I did...

When I arrived at the workshop I found some of my  beautiful rolled cleaving cement heads were burnt to a cinder. Everybody in the room knew that in order for the diamond to settle into the cement not only did the cement have to have the right temperature, but also the diamond. Well how could they heat both the stick and the stone to just the right temperature? They did have a clamp to hold the stone but God forbid if someone dropped it?

My brother said “Jaap, (Jacob) you do it”

I replied “OK”

Several weeks before I had already thought about how to do this job. Even when I made all the cement heads for the job I concluded that to set the stone would not be easy. Normally one would build a cement head for a cleaving stick by heating small pieces of hardened cement and slowly build it up to the required size, in this case I had poured them into shape.

One of my sticks had not been used, it had a head the size of a champagne glass. I made a hole in the centre. I took some strips of leather from my pocket and wound them three times around all my fingers, on both hands, then took an old fashioned spirit burner and a gas burner.

By gently heating both stone and cement I managed the job within ten minutes.

Amongst many tests we had done beforehand was an experiment with a grooving machine. It made an amazing screeching noise and to make a groove in a stone weighing one carat, took one hour!

“Give it a good old whack”

To make a groove in the Cullinan an enormous amount of scherp (sharp edged pieces of rough diamond to scrape away the groove) were prepared. This was a very expensive exercise, but given the task ahead, that didn’t seem to matter.

Joseph Asscher was a strong man, somewhat thickset, like Tommy Burns the then middleweight boxing champion. An hour after commencing the cleaving process both his hands were swollen. Rest? No that was not an option. A day and a half later the groove was ready. My brother Joseph thought that the special knives made by Herder were a little too long for this job, so  he asked me to shorten one of them. But how on earth do you quickly shorten an hardened steel blade. Use a grinder? Heat it and saw through it and then harden it again, much too complicated.

I knew exactly what I had to do. I went to the workshop and placed the blade in a heavy vice, and with all my strength gave an almighty hit with a sledge hammer! It broke in exactly the perfect place.

(On the 10th February 1908 in the presence of both John & Alexander Levy, all of the Asscher brothers, and witnessed by Hendrik Wertheim, Notary, the Cullinan was ready to be cleaved)

Two minutes later the blade was placed in the groove, Joseph hit it with power! The stone didn’t split. The blade flew through the room. Blade broken! Was shouted. “No not at all!’ I said “that’s just where I shortened it”. I gave him another blade slightly thicker this time and said, “Give it a good old whack!”  Again he hit it with enormous explosive power. “Crick” was the sound the stone made, it split into two, and both faces were as smooth as a mirror. The black inclusion was now in both pieces as intended.

Joseph drank two or three brandy and soda and grinned with satisfaction. Up to the present he is the ‘Undisputed World Champion’ in the cleaving of large rough diamonds!

Joseph cleaves the Cullinan.
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