264 DESCRIPTIONS OF MINERALS. 
Axinite. 
_ Ericlinie: = in acute-edged oblique rhomboidal prisms ; 
PAr=134° 45’, rAu=115° 38,, PAu=135° 31’. Cleavage 
indistinct. Also rarely massive or lamellar. 
Color clove-brown ; differing some- 
what in shade in three directions, being 
trichroic. Lustre vitreous. Transp 
rent to subtranslucent. Brittle. H.= 
65-7. G.=327. Pyro-electric. 
Composition. A unisilicate, afford- 
ing boron trioxide, and containing 
boron among its bases. One analysis 
afforded Silica 43°68, boron trioxide 
5°61, alumina 15°63, iron sesquioxide 
9°45, manganese sesquioxide 3°05, lime 
20°92, magnesia 1°70, potash 0°64= 
100°43. B.B. fuses easily with intum- 
escence to a dark-green or black glass, 
imparting a pale-e ereen color iD the 
flame, which is due to the boron. 
Dif. Remarkable for the sharp thin edges of its opel 
and its glassy brilliant appearance, without cleavage. ‘The 
crystals are implanted, and not disseminated like garnet. In 
one or all of these particulars, and also in blowpipe reaction, 
it differs from any of the titanium ores. 
Obs. Occurs at St. Cristophe in Dauphiny ; at Kongs- 
berg in Norway; Normark in Sweden; Santa Maria, “in 
Switzerland ; Cornwall, England ; Thum in Saxony, whence 
the name Thummerstein and Thumite. 
In the United States it has been found at Phippsburg and 
Wales in Maine; and at Cold Spring, New York. 
Danburite. A silicate which contains, like axinite, pork trioxide. 
Composition : Silica 48-8, boron trioxide 28:5, lime 22°7. Occurs with 
oligoclase and orthozlase in imbedded masses of a pale-yellow color, 
at Danbury, Conn. H.=7. G.=2:95-2:96. 

‘ Iolite.—Dichroite. Cordierite. 
Trimetric. In rhombic prisms of 120°, and in 6 and 12- 
sided prisms. Also massive. Cleavage indistinct : but erys- 
tals often separable into layers parallel to the base, especially 
after partial alteration. 
Color yarious shades of blue, looking often like a pale or 
