New Minerals from Texas, Lancaster Co., Penn. 249 
The mean of three trials gave 11-691 of CO*. A trace 
magnesia in the specimen examined was disregarded, as being 
asis of carbonate of magne 
which is difficult to separal 
The constitution resul 1 the analysis is— 
Atoms. 
5881l 2622=3 
Oxyd of nickel, : 
Carbonic acid, : : 11-691 423 =1 
Water, , ‘ ; ; 29-498 12°52 = 6 
This gives the empirical formula, 3Ni+C46H=NiC+2Ni 6EF, 
or NiO+ANR, ). 
n-we remember the isomorphism of magnesia and oxyd 
of nickel, it will be agreed by all who attach any value to this 
agency in modifying minerals, that we may have many cases in 
which these two oxyds are mutually interchanged. Hence we 
find at the Texas locality, dolomitie carbonates with a faint tint 
of green derived from a small trace of oxyd of nickel present in 
them—others of green color several shades deeper, and others 
which closely approach the high color and other pa of the 
pure hydrous carbonate of nickel described in th r. In 
some specimens, unquestionable emerald nickel te nae | mechan- 
ically mingled with and coating whitish dolomite. I cannot 
agree with the opinion expressed by Prof. Shepard, at page 
of this volume, that these varieties are distinct species. tai 
we must demand analyses to show that the Mg O and NiO arein ~ 
fixed atomic proportions with water, before the “hydrated carbo 
hate of magnesia and nickel” can be regarded as a true species. 
Analy tical Laboratory, August, 1848. 
Ze 
Arr. XXVI—On new Minerals from Teras,. YT cmcahiee Con 
Penn. ; by Cuarves Urnam SHEPARD, M.D. 
Williamsite. 
: composition lamellar, individuals of tee size, 
renites isizhe, rather difficultly separable. Faces of ¢ 
sition not very even. Fracture even. Surface nearly dull, 
Lustre feebly shining, pearly to resinous. Color apple-green. 
Streak white. Translucent. 
Hardness = 4-5. Sp. gy. = 2:59... 2°64. 
» Before the yi tel it phosphoresces, turns white, an 
ns so as to scratch glass, but does not fuse. It dissolves with 
ponies difficulty in borax, without imparting any color or opacity 
to A ae In powder, it dissolves chet B in hot hydrochlo- 
ric aci 
