124 Fourth Supplement to Dana's Mineralogy. 



NITE.AMMITE. — Prof. SheparJ (his Miu. p. v) gives this name to nitrate of 

 ammonia, "which he states he has detected in the nitrous earth of the cavern at 

 Nicojack, Tennessee. 



Opal [p. 151, and IH]. — Prof. Shepard describes under the name of GlossecolUtej 

 a milk-white hydrated silica, for "which he writes the formula 5ifi, and states that 

 it loses 17 per cent of water by ignition. [This is the composition obtained by von 

 Kobell for the Mkhaelite (Si 83 65, fl 16'35)]. It occurs earthy compact and white 

 or brownish, yellowish ; adheres to the tongue (to wliich the name GlossecoUite 

 alludes). H.^2 — 25. G.^2-2 (but 1*7 if previously varnished). It constitutes a 

 seam an inch thick in a siliceous rock belongmg to the Upper Silurian, and "appears 

 to have originated in the alteration of a layer of hornstone." Fonnd 2^ miles south 

 of Rising Fawn, Dade Co., Georgia. Shep, Min. p. iil 



Palladium Ochre. — The palladium ochre, which has still a doubtful existence, is 

 called Falladinite in Shepard's Min., p. 408. 



PAEASITE, — A name given by 0. Volger to a borate resulting from the altera- 

 tion of boracite, probably containing magnesia, water and boracic acid. It is in 

 feathery crystallizations within the boracite crystals, and is optically biaxial probably. 

 —Fogg., xcii, 77. 



Parastilbite [p. S32].— Von Waltershausen adds the following to his description 

 of this mineral (Pogg xcix, 170)— Form trimetric, resembling epistilbite [see Min., 



p. 3S0], l^ : IT (top) =110^ 61'; 22 : 22 (over brachyd. pyramidal edge) 136=^ 38-7'. 



^ PAEATHORITE, /SAfparcZ— Described by Shepard (Shep. Min., 287) as occur- 

 ring in minute pitch-black crystals, which are square prisms {it) with truncated 

 lateral edges (/), and pyramidal terminations; the pyramids consisting of the 

 planes of two octahedrons m and 7/i', in the same vertical series with L m (face of 

 the terminal octahedron) : n— 130° ; m : »i'=160^ ; /: n=135^ ; ii : n=90°. Faces 

 bright. Cleavage imperfect. H.=5 — 6. B.B. infusible but turns brownish-red, and 

 has a semi- fused aspect at the point most heated ; with borax fuses easily to a glass 

 colored by iron. Found at Danbury, Ct. with danburite and oligoclase, and named 

 from a supposed resemblance to thorite. 



[This mineral was first described by Prof. Shepard as Thorite in the Proceedings 

 of the American Assoc, iv, 321 (New Haven meeting). The crystal figured is there 



stated to be ^V ^°' ^^^Sj ^^*^ ^^^*' ^°® ^^ ^'^® octahedral planes m' w^as observed, 

 7n : ii is there given as 120° and not 130°. The form was obscure and irregular as 

 the angles given show, since 98° for ?n: 772 would not give 120° for 7?i:2i ; moreover it 

 would give 158° 7' for m :/(the prism), while 160° is stated to be the angle of m : m', 

 making tti' nearly coincident with /, which it is far from being in the figure. Having 

 examined minute crystals of this mineral from Danbury, I find the form to be tri- 

 metric, the crystals being either rhombic or rectangular prisms. One of them, a 

 rectangular prism with replaced edges, has a general resemblance in the terminating 



planes to the form figured by Professor Shepard, although too indistinct, owing to 

 the curving surfaces of a considerable part of the summit to be satisfactorily figured. 

 Another, a very regular rhombic prism, having the acute edges truncated, gave for 

 the prism the angle 128°; and for the prismatic planes on it 116°. The crystals 

 vary in color from pitch-black to translucent garnet-red, and even in the black crys- 

 tals splinters or thin edges have often a ruby translucence a little like rutile. TLey 

 are very commonly imbedded in the Danburite. The following are the blowpipe 

 characters as communicated for this place by Prof. G. J. Brush.— ^. n. n.] 



Note on the blowpipe characters of Parathorite, by G. J. Brush. — In the matrass 

 decrepitates slightly, but does not appear to contain water. In the platinum forceps 

 glowri, fusea with difficulty on the edges, and becomes paler. In borax dissolves to 

 a bead which is yellow (due to iron) while hot, and colorless on cooling. With salt 

 of phosphorus gives a bead in the outer flame, which is yellow while hot and color- 

 less on cooling. In the inner flame the bead assumes a delicate violet color (titanic 

 acid?). Hardness about 5. The crystal examined minute. 



Viz^sissu — See Chlorite^ 



Peeofseite [p. 345 and IIJ. — In mentioning the remarkable locality of Perofskite 

 fotmd in the valley of Zewnatt, in Supplement II, it should have been added that 



