Alchemy. A substance in an early stage of its preparation. Obsolete. rare.

Alchemy. The red form of the philosopher's stone. Now historical.

(a) = red stone, n. 2; cf. sense A. 3a; (obsolete); (b) a stone or jewel consisting of ruby, or of a ruby colour.

a substance regarded as the female principle or parent of metals, usually identified with mercury (cf. mercury, n. 8).

transferred in Alchemy. (Cf. heaven, n.)

A supposed volatile substance or chemical principle related to or present in saltpetre, said to exist in the air or in plants and to give rise to…