In the so-called " blue ground " of the tarm Koppiesfontein, in the neighbourhood of Jagersfontein, Orange Free State, a prospecting shaft was put down; and in the 110 ft. level struck a blue-grey, soft, and apparently talcose serpentine-like mass. The latter was densely studded with a great number of small, completely formed, light coloured crystals, which in some places lie very close together. The crystals may be easily isolated from this matrix, in which they leave smooth-sided and sharpedged moulds.