ipo EARTHS. CALCAREOUS. 23. Magnefiata. 



23. MAGNESIATA. Confifting of carbonate of 

 lime, a little black oxyde of manganefe, carbomc 

 acid gas, and water : hardiih, lamellar, fponta- 

 neoufiy feparating into grains : gradually chang- 

 ing the colour of its furface when expofed to the 

 air, effervefcing (lowly with acids, and often 

 pot without trituration : becoming black in the 

 fire. 



^ranularis. Subopake, tranquil in the fire, breaking into indetermi- 

 nate fragments, of a common form* 



Sidero^calcite, Kir^^an mitieraL I. /. 105,. 



Brown fpar. SchmeilJer mineral, i, p. 22^. 



Brown fpar, Thomjan chem. 3. ^, 612. 



Found in various parts of Germanjy StveJent Fraf!ce, Sec. in 

 large mafles : colour white, fiefh and rofe-colour, greyifh, 

 yellowifh and rcddifh-white, with frequently an irridefcent 

 apiietallic appearance : generally opake, and becomes brownifh 

 when expofed fome time to the air: fpecific gravity 2,837. 

 contains carbonate of lime 50. oxyde of iron 22. oxyde of 

 ^nanganefe 28. Bergman, 



Jexuosa* Shining internally, making a grey mark, breaking into 



indeterminate fragments, with the foliations in- 

 curved. 



Karst, Lejke mineral. I.;i. 274, 



t]offmann Berg. Journ, 1789, i. /», 191, 



Found in Hercynioy and ne^r Cam/dor/ a.nd Scharheni^erg in S^ive- 

 dent reddifh or greyilh-white. 



spatosa. A little fhlning internally, rnaking a grey mark, breaking 

 into rhomboidal fragments, with the foliations 

 ftraight, 



Karst, LeJke mineral. I. /. 273. 



Hoffmann Berg. Journ, 1789. i. p. 189. 



1. Of a common form. 



2. Kidney- fhaped, 



(3. Cryftallized ; the cryftals often very fmall, fometimes kattercd, 

 fometimes cluftered in a feries. 



a. licnticular. 

 Common. 



Curved like the beak of a faddle. 



b. Rhombic. 



With the faces flat. 

 With the faces coi^vex. 



