CALCAREOUS SPAR. 



115 



zerland, at Hall in the Tyrol, at Ischil in Upper Austria, 

 Wieliczka in Poland and elsewhere. 



Uses. The vulpinite variety is sometimes cut and polished 

 for ornamental purposes. 



calcite — Calcareous Spar — Carbonate of Lime. 



Rhombohedral, (fig. 1.) R : R = 105° 5'. Cleavage easy 

 oarallel with the faces of the fundamental rhombohedron. 

 2 3 4 5 



1 



<^^ 



Figure 1, is the fundamental rhombohedron ; figure 2, is a 

 flat rhombohedron with the lateral angles removed, sometimes 

 called nail-head spar ; figure 3, is a six-sided prism ; figure 

 4, an acute rhombohedron ; figure 5, a scalene dodecahedron, 

 the form of the variety called dog-tooth spar. Figures 28, 

 28a, 30, 31, page 32 ; 62, 63, page 39 ; and 66, page 40, are 

 other forms. Calcareous spar also occurs fibrous with a 

 silky luster, sometimes lamellar, and often coarse or fine 

 granular and compact. 



The purest crystals are transparent with a vitreous luster ; 

 the impure massive varieties are often opaque, and without 

 luster, or even earthy. The colors of the crystals are either 

 white or some light grayish, reddish or yellowish tint, rarely 

 deep red ; occasionally topaz yellow, rose or violet. The 

 massive varieties are of various shades from white to black, 

 generally dull unless polished. H=3. Gr=2*5 — 2*8. 



Composition : lime 56*0, carbonic acid 44'0 : sometimes 

 impure from mixture with iron, silica, clay, bitumen and 

 other minerals. Infusible before the blowpipe, but gives 

 out an intense light, and is ultimately reduced to quicklime. 

 Effervesces with the acids. Many varieties phosphoresce 

 when heated. 



What is the fundamental form of calcite or calc spar ? What are iti 

 olors and appearance ? What is its composition 1 



