"Who Would Have Thought Human Hands Capable of Such a Feat?" The work of my maternal grandfather, Anton Alberse, a diamond-cleaver.

A good friend was asking about the work of my maternal grandfather, Anton Alberse. He was a diamond cleaver.  Cleaving diamonds is very difficult, challenging work. Very few individuals have the courage and patience to become diamond cleavers. It requires exceptional concentration, plus nerves of steel. 

 Antwerp - one of the great European cities where my grandfathers and father 
worked (the other city was Amsterdam).

In my boyhood, before WWII, often I brought my grandfather his lunch and so I got the chance to see how it works. (More about this below.) Grandfather would prepare by setting the rough diamond on top of a tapered wooden stick with a special cement head.   

Before this step, he would mark with pen and Chinese ink the ‘veins’ where he thinks he will cleave. The ‘cement’ was made of shellac, and resin, and some other ingredients, including diamond-powder.  When the cement head was heated, it becomes soft and sticky but then becomes rock hard when cool. 

Then he’d take another diamond with a sharp edge (also set in a stick), and use that to make a V-shaped groove in the stone that’s going to be cleaved. Only diamond can cut diamond. And here’s the tricky bit:  that groove has to be made exactly on the growth plane of the stone (and there are four growth planes for a diamond). 

Once the groove is deep and sharp, then he’d take a blunt metal blade and insert it into the groove. Then the final step:  a short, sharp hit with a wooden mallet, to split the stone in whatever number of pieces his boss told him to create. These smaller stones go to the diamond-facetter (such as my father), who transforms them into jewels. 

Like I say, the studying and focusing before cleaving can take some time.  Sometimes the correct spot is missed and the raw diamond shatters.  This would cost the “boss” lots of $!  When something shatters or breaks not as planned, the cleaver then has to sweep up all the pieces. If the pieces are very small, then everything is put into a fire, what does not burn, is diamond. So you can imagine the pressure a diamond cleaver lives with.  At least in those days.  

Today this work is done with the aid of machines and computers. The more accurate a cleaver is, the more he got paid. Like I mentioned, often I used to bring grandfather his lunch.  Imagine this:  I was about six or seven.  Grandfather worked in a small room, there was one window, with bars (for security).  

Outside the door were two lights – green and red. If the green light was on, I would go in.  If it was red, I’d leave his lunch outside the door.  I knew the red light meant he was either about to cleave a diamond or in a state of intense concentration. With a green light, I’d enter with his lunch, and we’d chat while he ate.  But as soon as he was ready to resume work, I had to stand in the corner, be very still, and silent. Then I went back to school. 

Unfortunately I do not have a photograph of my maternal grandfather, who passed away many decades below.  But since we are talking about diamonds, here is a photograph of my grandfather's son -- my father -- who was a diamond-facetter.

My father, diamond-facetter Johannes Antonius van Bentum, circa 1950's