ORDER in. PYRAMIDAL PEARL-KER ATE. 157 



2. i^-ipS. ^P 2. P + oo. [P + oo). 

 Sim. Fig. 102. 



Cleavage P + OD very indistinct. Fracture perfect 

 conchoidal. Surface smooth. 



Lustre adamantine. Colour yellowish-grey or ash- 

 grey, also yellowish- and greyish-white. Streak 

 white. Translucent, sometimes only on the 

 edges. 



Sectile. Hardness = 1-0...2-0. Sp. Gr. - 6 482. 



Compound Varieties. Crystalline coats, proba- 

 bly formed originally upon globules of fluid mer- 

 cury : composition not observable. Massive : com- 

 position granular. 



OBSERVATIONS. 



1. The mixture of pyramidal Pearl- Kerate is expressed 

 by Hg M , which corresponds to 



Oxide of Mercury 88-48. 



Muriatic Acid 11-52. 



Before the blowpipe, upon charcoal, it is entirely volati- 

 lised, if pure. According to GMELIN, it is not soluble in 

 water. 



2. This rare mineral occurs in the repositories of peri- 

 toraous Ruby-blende in secondary rocks, sometimes upon 

 veins of Iron-ore ; it is accompanied by various ores of 

 mercury, also by ocbry varieties of prismatic Iron-ore, &c. 



3. Its chief locality is Moschellandsberg in Deuxponts, 

 but it occurs also at Idria in Carniola, and Almaden in 

 Spain. At Horzowitz in Bohemia it has been found with 

 peritomous Ruby-blende in veins traversing a bed of Iron- 

 ore. 



