CATALOGUE OF GEMS. 



523 



loMi;- iiiul 8 feet in diameter are not unconnnon. The locality ati'ord.s 

 perhaps the finest specimens known for warmth and combination of 

 coh)rs, in which red predominates. (Fig. U.) 



Amethyst. — A clear purple or l)luish violet (quartz. The color of 

 the amethyst is often irregularlj^ diffused, the deep purple fading into 

 pink and white. (See tig, 10.) 



A^stt-rkded or atar quai'tz. — Contains impurities or opacity so arranged 

 that when cut cabochon across the prism it exhil)its asterism. 



Aventurine quartz is minutely spangled throughout the mass with 

 yellow scales. It is transparent to opaque, and of a gray. 1)r()\vn, red- 

 dish-brown, or yellow color. 



Basanite, lydlandone, or ioi«-Ji.sionc. — A velvet-black silic(M)us (juartz 

 or flint}' jasper. 



Beehite. — Silicitied corals, shells, or limestones, resembling chal- 

 cedonv. 



