Uncle Peter wrote:


Carborundum was a man-made product produced in electric fired furnaces
in the New York region IIRC.. I have a few examples ofearly carborundum
fixed
detectors in my collection. Whether the product is still being commercially
produced is another thing, but it did exist at one time...

Carborundum is the abrasive used in any of the "black" sand papers, such as
the brand name "wet-or-dry". It is a trade name for silicon carbide.

Originally carborundum was a mined mineral called moissanite. But now it is made
using an electric furnace to combine silica sand and carbon. It is such an easy
process you could make carborundum crystals at home if you wanted to.

Carborundum was the initial product mined by the company we now know as 3M. Back
then the company was known as Minnesota Mining and Manufacturing. They were the
first to find a reliable way of putting carefully graded and sized carborundum
granules on a piece of waterproof paper. In essence, they invented "sandpaper".

-Chuck