Sapphire. 85 obferved yellowifh white, and laftly it paffes from ^vender blue into pearl grey, blueifh grey, and blueifh ' v hite. ^erner fuppofes that the yellowifh white may pafs lilto yellow. ^ is fometimes found with two colours at once, as ^'te and blue and blue and red. Werner has in s Pofleffion a fapphire which is white in the middle, ail( i at the one end blue and at the other red. ^ occurs in fmall rolled pieces, and cryflallized. ts Cr yftallizations are as follows: *• Double three-fided pyramid, in which the lateral planes of the one are let on the la teral edges of the other ; or it may be cou- fidered as a flightly acute rhomboid. 2. The extremities of the pyramids (or the two diagonally oppofite angles of the rhomboid) more or lefs deeply truncated, and fome times fo deeply that there is formed a fix- fided table, in which the terminal planes are fet alternately oblique and flraight on the lateral planes. 3- Sometimes the common bafis of the pyramids is truncated, and in lbme varieties fo deep ly, that there is formed a lhomboidal fix- fuled prifm acuminated by three plants, which are fet 011 the alternate lateral edges. The extremities of the acuminations are often truncated. 4- Terfecl fix-fided prifm, which is fometimes fo Qiort that it forms a fix-fided table. 5. Six-