ALUMINA. 329 



SCAPOLITE. 

 [From the Greek lixans, a rod, and "Kiks, a stone ; in allusion to the rod-like appearance of the crystals.] 



Paranthine, Wemerite, Meionite, and Dipyre. Ha^y. — Scapolite, and Meionite. CkaveUmd. — Meionite or 

 Scapolite, and Gabronite. Thomson. — Scapolite, and Nuttalite. Phillips. — Pyramidal Feldspar or Scapolite, 

 and Meionite. Jameson. — Pyramidaler Elain-Spath. Molis; and Nuttalite. Mohs (App. II. 660). — Meio- 

 nite, and Wemerite. Beudanl. — Scapolite. Shepard and Dana. 



J'g- ^^' Description. Colour, white, grey, green, yellow or red. It occurs regu- 



larly crystallized ; also massive and disseminated. The primary form 

 is a right square prism, Fig. 279 ; but it often occurs in prisms of eight 

 or twelve sides, variously terminated and sometimes aggregated late- 

 rally. Cleavage parallel to the sides, terminal planes and both diagonals 

 of the primary. Fracture conchoidal and uneven. Lustre shining, pearly, 

 resino-vitreous and resino-pearly. From transparent to opaque. Brittle. 

 Hardness from 5.0 to 5.5. Specific gravity from 2.50 to 2.75. By 

 calcination, it gives' off water without losing its transparency. Before 

 the blowpipe, it fuses with intumescence into a colourless semi-transparent mass ; with borax, 

 with effervescence into a transparent glass. It is attacked with difficulty by the acids, the 

 solution being precipitated by oxalate of ammonia. 



Its crystalline form, specific gravity, and inability to become electric by heat and to form a 

 jelly with acids, will serve to distinguish scapolite from some varieties of zeolite, stilbite, etc., 

 which it often resembles. 



The different varieties of minerals belonging to this species were found at different times ; 

 and not resembling each other in their external characters, they received different names. 

 Thus, Haiiy describes as distinct the Meionite, Wemerite and Paranthine, although his figures 

 of the crystalline forms of the three minerals are almost exactly similar. Subsequent crys- 

 tallographical examinations and chemical analyses have sufficiently established their identity ; 

 and they are now, with some other varieties, usually included under the name of Scapolite. 

 Meionite. This includes the white, more transparent and highly crystallized varieties. 

 Scapolite. It consists of the translucent and opaque crystals, and the massive varieties 

 which are tinged green, black and red. 



Wernerite. This name is usually applied to the crystallized variety, which has a greenish 

 or greenish grey colour. 



Nuttallite. This name was given by Brooke to a variety which has a grey or bluish colour, 

 and is softer and has a more vitreous fracture than common scapolite. It also possesses a 

 play of light on the faces of the prism, similar to that of elaolite. It is, however, identical 

 in crystalline form and composition. 



Paranthine includes the more compact varieties. It has a pure white or pale blue colour ; 

 while Dipyre is of a grey or reddish white colour, and becomes slightly phosphorescent on 

 the apphcation of heat. 



MiN. — Part II. 42 



