PHYSIOGRAPHY. 



Humite. 



271 



Secondary form. 



Fig. 254. 



P on /or h 

 Mon h 

 M on dl 

 Mon/ 

 P on cl 

 P onc2 

 A on a 

 A on dl 

 A on d'2 

 A on d3 

 A on d4 

 A on do 

 A on t/6 

 A on d7 * 

 A ond8 

 A on d9 

 A on dlO 



Cleavage, traces parallel to M and h, or to a six-sided prism. 



Fracture imperfectly conchoidal. 



Lustre vitreous. Color various shades of yellow, sometimes al- 

 most white, passing into reddish brown. Transparent . . . translu- 

 cent. 



Brittle, Hardness = 6-5 ... 7-0. 



1. Alone before the blow-pipe, it becomes opake on the outside, but is 

 infusible. It gives a clear glass with borax. 



2. It occurs at Monte Somma, with Mica and various other minerals. 



3. Several of the properties of Humite would seem to render it proba- 

 ble that it may be identical with Brucite. At present, however, the 

 crystalline forms of the latter substance oppose this union of the two min- 

 erals, although it must be confessed that Brucite has never been found 

 in perfectly formed crystals. 



