Diatomite from the Muir of Dinnet, Ballater, Aberdeenshire.

BGS image ID: P527720

A collection of specimens of diatomite from the deposit at Muir of Dinnet near Ballater, Aberdeenshire. 

Diatomite is a whitish, fine-grained substance consisting essentially of siliceous skeletons or frustrules of diatoms, minute organisms. British Geological Survey Petrology Collection sample number MC 7497. 

Most diatomite is laid down in freshwater lakes and swamps. This deposit was first recognized as diatomaceous by the Rev. George Davidson in about 1880. An analysis by Mr. Ivison Macadam showed that the inorganic portion contained 82.96 per cent silica, 5.5 per cent iron oxide, 2.1 per cent alumina and 2.93 magnesia. It compared with the specimens of German kieselguhr for purity. 

The deposit was explored by sinking shafts and it was estimated that the deposit contained 800,000 cubic yards of kieselguhr, 6 cubic yards of which, when fully dried would make a ton. The diatomite occurred at a number of localities: Black Moss, 162 acres in area, 15 feet to a few inches thick and 800,000 cubic yards; Ordie Moss, originally 8 acres but now worked out; Loch Kinnord; Haugh of Milton 10-12 acres, one foot thick 17,700 cubic yards; Auchnarran, 46 acres, 15 inches thick 92,700 cubic yards.

Almost all the diatomite went to the Ardeer explosive works in Ayrshire where it was used as a carrier or absorbent for nitroglycerine in dynamite manufacture. (Good diatomite will absorb four times its weight in water.)



Bob McIntosh