282 Cross and Hillebrand — Some interesting Minerals 



The most perfect one measures 2 - 5 cm parallel to the vertical 

 axis, 3'3 cm parallel to the brachy-axis, and 2"8 cm parallel to the 

 macro-axis. It is colorless, and some parts of the crystal are 

 very clear. The prisms I{ooP) and i-2 (ooP2)'are well 

 developed. The terminations are drusy, although many of the 

 prominences are large enough to admit of the determi 

 some of the faces which bound them. The pyramid 2 (2P) 

 has been recognized with certainty, while a form between 

 |(1P) and 1(P), which is probably"! (fP), and another pyra- 

 mid near 2-4 (2P4) are also present. Measurements of suffi- 

 cient accuracy for the calculation of these latter forms could 

 not be obtained. The lateral edges of these pyramidal promi- 

 nences lie in a plane corresponding to the brachydome 

 2-t(2Poo), and although that form does not actually appear, 

 crystal has a domatic habitus. A rough face of 4-z'(4Pco) 



is 1, 

 t ■ rl< 



ect than the other, both are alike. 



The second crystal is less perfect. The prism i-2 ( ooP2) pre- 

 dominates, and tin' terminations are low and indistinctly drusy. 

 The crystal measures ~> cm parallel to the maero-diagonal, and 

 has a slight greenish tinge. 



The third crystal, or rather fragment, was found recently 

 near Florissant, northwest from Pike's Peak, with Amazon 

 stone, etc. It is mainly noteworthy on account of the enor- 

 mous size of the original crystal from which it came. This 

 specimen is but a corner of a large crystal, the forms ;. 

 being two faces of i-2 (ooP2), one of J(aoP), and one each of 

 %i and 4-i. The fragment is about 9 cm (3} in.), in its longest 

 diameter, and if the other faces were developed to correspond 

 to those here seen, the complete crystal must have been nearly 

 or quite one foot in diameter parallel to the brachy-diagonal. 

 It is clear in parts and has a decided greenish tinge. It was 

 supposed to be fluor spar, by the original collectors, and the 

 other pieces of the crystal are undoubtedly lost. 



The specific gravity of this fragment is 3-578 at 22° C, and 

 its chemical composition is entirely normal. 



