330 fipodumene and its Alterations. 



between the psendomorphoiis crystals and the quartz-gangue, 

 so that a slight blow of the hammer releases them in an unin- 

 jured condition. 



Hardness, 1.5 to 2. Specific Gravity, 2.700 (determined on 

 5.7 grammes of coarse powder), 2.696 (determined on 5.5 

 grammes, in a lump, long digested to expel air). Lustre in- 

 termediate between silver and satin, but seeming to approach 

 the latter, on account of the fibrous texture. Color, white to 

 vellowisb, also often stained by films of Ochre or Pyrolusite. 

 Laminae brittle, and only separable with difficulty, or not at all 

 in the larger compact masses. Translucent on thinner edges. 

 Feel, soft. 



Pyrognostic Character. — In platinum forceps, it fuses on very 

 thin edges (6), and the surface of the splinter becomes covered 

 with a white and translucent blebb}^ enamel. A fragment, 

 moistened with solution of cobaltic nitrate, gives the alumina 

 reaction without difficulty. In a matrass at high temperature, 

 it yields a little water, and a small amount of ammonia, indi- 

 cated by a feeble odor but distinct reactions with test papers, 

 etc. In borax bead, it dissolves readily, with effervescence and 

 in large quantity, to a clear bead, with the yellowish iron re- 

 action while hot ; gradually displays a siliceous skeleton ; and 

 at saturation becomes clouded by silica and bubbles. In phos- 

 phoros-salt, as in borax, but with immediate formation of the 

 siliceous skeleton. Insoluble in acids. 



Analyses of Cymatolite. — In the columns below are given the 

 res\ilts of four analyses of the common wavy variety of this 

 mineral, which was found in abundance at the Chesterfield 

 locality. 



VI and VII — Cymatolite from Chesterfield. Analysis in du- 

 plicate of the average material derived from a mixture of frag- 

 ments of about forty different crystals, white and yellowish- 

 white in color, taken at random. 

 VIII — Mean of the foregoing two analyses. 



IX — Cymatolite from Chesterfield. Analysis of a slice across 

 a complete pseudomorphous prism, of the radiated fibrous struc- 

 ture and white color, about an inch in diameter. Apparently 

 it was completely altered to pure Cymatolite, but the increased 

 amount of lithia in the analysis may indicate the presence of 



