SRG Mailbag
Dear Slippery Rock Editor
The article by Sharon Koehler (February SRG) reminded me of my first visit to the Zimbabwe Ruins in 1949 (yes, not a misprint, 1949!). As a young boy I was totally fascinated by the ruins and the story we were told was that these might easily have been King Solomon’s mines. Somehow I seriously doubted that, so I have looked up the known history and found that they were built by the Shona tribe in the 12/13th century.
However, this whole article about Zimbabwe interested me very much and it brought back another memory, this time a little closer to today, as this happened in 1974/75. For those with a historical bent, you might recall this was after U.D.I. when the white settlers were fighting a revolution by the same Shona tribe.
It was at this time that Zimbabwe Black granite was first discovered, and the company I managed started exporting it, thus necessitating a trip for me to visit the quarries. This was a little more complex than appears because the quarries were in the direction of Mozambique and this was the rebels’ hideout if the army got too close. As a result the whole area was closed to regular civilian traffic, but with special permission and timing of the trip to coincide with troop movements, one was allowed to travel in a convoy from Salisbury to Mutoko Hills.
Some of you may recall having done business with Murray Gouldstone, and as he had been with the British South African police force, but was now a representative for Impala granite in Rhodesia, he arranged the trip with an army convoy.
So about 5 or 6 of us got into a Land Rover with 4 or 5 army transporters ahead of us and an equal number behind. About 15-20 miles from the quarries the convoy waved us goodbye and was careful to wish us good luck as they disappeared down the road, leaving us in the solitary Land Rover, driving down dirt roads to the quarries. Just before getting there we were met by two armed guards who told us that we had to abandon the truck, walk the rest of the way and they would act as our bodyguards as, I repeat, this was all rebel territory. After a few minutes’ walk the lead guard got a couple of 100 yards ahead, as he was used to walking the jungle and we were not. Suddenly we heard a gun go off, so we all thought we were being attacked by rebels. I promptly dived to the ground and had the privilege of having 4 or 5 fairly heavy gentlemen, to include Murray, piled on top of me.
Let’s say that it was most uncomfortable, but I was buoyed by the thought that when the Assegai (stabbing spears) guys came, I would be on the bottom and thus protected! However, nothing further happened and after 15-20 minutes we stood up, dusted ourselves off and continued walking. When we got to the quarry we discovered that the reason for the shot was not rebels, but our guard had shot a Guinea fowl for lunch! There was much rejoicing by all. The rest of the trip was uneventful, and we returned to Salisbury late that evening.
Concerning Zimbabwe Black granite, once it arrived and was sold in North America, we discovered a peculiar phenomenon: sawn slabs looked perfect, but some polished slabs would show a black “knot” about the size of a baseball, generally circular. One of my customers, Mr. Marc Bussiere (of Bussiere Granite, Megantic, Quebec), found a solution to the problem by wiping the spots down with diluted muriatic acid, after which they would disappear.
A friend of mine, Dr. William B. Size, was a professor of geology at Emory University, so I asked him what could cause this problem. He investigated and inspected a few pieces of stone with the defect clearly visible and gave the following explanation: Zimbabwe Black is an igneous rock, and was basically formed by eruptions from down below.
During these eruptions, some molten lava would be spewed into the air and, due to surface tension, become ball-shaped, after which it would fall back into the remaining magma. However, that meant that these granite balls were in fact much denser than the surrounding material because the curved shape had reduced the volume. When these balls fell into the surrounding magma they melted once again, forming an integral part of the block so that, when it was sawn, you did not see this. However, under the polishing process, because these balls were denser and a little harder than the surrounding stone, they would take a deeper, darker gloss which became visible. The muriatic acid treatment aforementioned would simply attack the highly polished surface and tone it down a little to blend with the remaining material surrounding the balls. Suffice it to say that it worked, and that Zimbabwe Black is still being exported to this day some 45 years later!
Yours sincerely,
Peter T. de Kok