Zircon. characteriftic of zircon), from this into plumb blue, and columbine red; and laftly into yellowifh and reddifh brown. The colours are fometimes dark, fometimes very dark, and alfo light; and from their falling more or lefs into grey are always a little muddy. It occurs molt commonly in roundifh angular pieces, which have almoft always rounded angles and edges. Alfo cryftallized ; the figures of its cryftals are as follows: 1. A rectangular four-fided prifin fomewhat flatly acuminated by four planes, which are fet on the lateral planes. Of this figure the following varieties occur: i- ihe lateral edges truncated. 2. The angles formed by the acuminating. and lateral planes bevilled ; when thefe in- creafe, 3. Very acute eight planed acumination is formed. 2. A very flat odaedron which is formed by the meeting of the two acuminations. It is either perfe£t, or the edges or angles on the com mon bafis are truncated. 1 he cryftals are always fmall and very final!, \ery e om middle fized, and ftill feldomer large, ey are all around cryftallized (am und am crystal- j confequently have been formed imbedded. ^ Surface of the cryftals generally fmooth, and, when tt as been well prelerved, is Aiming, bordering on rongly fplendent j that of the angular pieces is fometimes