From STRONTIAN. S 



a centre. The uniformity of this radiation is frequently in- 

 terrupted by the fibres proceeding from different points of con- 

 vergence, croffing and interfedting each other. Occafionally on 

 the furface, but more frequently in vacuities within the mafs, 

 the mineral is difcovered (hooting into flender prifmatic or co- 

 lumnar cryftals of various lengths. Some of thefe end obtufe- 

 ly, others of them in a (harp point ; they are generally ftriated, 

 and have fix fides. I have feen thefe cryftals traveriing the cavi- 

 ties in the form of the fineft and moft delicate fpiculse, and 

 when difpofed in a radiated form, equalling in delicacy, and 

 refembling in appearance, the moft exqulfite zeolites. In other 

 portions, the ftriated fibrous contexture is fcarcely difcernible. 

 Sometimes the Strontian fpar is tranfparent an 1 colourlefs, more 

 commonly it has a tinge of yellow or green, and fome diver- 

 fity is obfervable in the depth of the tint. 



4. It is not fo hard as to fcintillate ; it may be fcratched by 

 a knife ; it readily yields to the ftroke of the hammer ; it has 

 no particular fra(5ture, though it commonly breaks along the di- 

 re<5lion of the fibres. 



5. It is a heavy fpecies of fpar, having a fpecific gravity, go- 

 ing between 3.650 and 3.726. 



Chemical ^alkies. 



6. This mineral to the tafte is infipid, and is only in a fmall 

 degree foluble in water. 1 boiled ten grains of it, reduced to 

 a very fine powder, in four ounces of diftilled water for fomc 

 time ; about two grains and a half were dlffblved. 



7. It is powerfully attacked by feveral of the acids, and a fo- 

 lution takes place in fome of them. This is accompanied by a 

 lively and brifk eflPervefcence, which in this as in every other 

 inftance, proceeds from the difengagement of an aerial fluid. 



8. The gas that arifes during a folution of this mineral in 

 muriatic acid, extinguiflies the flame of a candle, and is ab- 



forbed 



