Kieselguhr

Kieselguhr is an earthy deposit consisting almost entirely of the siliceous remains of microscopic organisms - diatoms (q.v.). It occurs largely in white and grey deposits near Hamburg, and before being applied to its various uses is calcined in kilns built for the purpose. It is largely used as a polishing powder, in the manufacture of ultramarine and firebricks, while large quantities are employed for the manufacture of dynamite. [Nitroglycerine.]