PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 70 



leucophoenicite is almost always present in small clear rose to pur- 

 plish red prismatic crystals. The presence of this clear leucophoeni- 

 cite is a good indication that chlorophoenicite may be present. 

 Calcite occurs massive and covers many of the earlier minerals or 

 is found as small hexagonal prisms. The chlorophoenicite is perched 

 on all these minerals or rests directly on the franklinite-willemite ore, 

 but rarely is inclosed in some calcite. The crystals are haphazardly 

 arranged although they show at times a crudely radiating grouping. 

 Two types of crystals were distinguished, long needle-like crystals 

 forming an open reticulated mass or short, stumpy ones forming 

 small groups of a few individuals or small crusts. 



Several other arsenates have been found in the same workings 

 from which the chlorophoenicite came, notably the silico-arsenate 

 of manganese, schallerite and the arsenate of calcium and lead, 

 hedyphane. 



CRYSTALLOGRAPHY 



All the chlorophoenicite occurs in distinct crysltals that reach a 

 maximum size of 8 mm. in length and less than 1 mm. in thickness. 

 The needles are always deeply striated parallel to the elongation 

 and the terminal faces are etched and dull. Measurements of the 

 crystals showed that they belong to the monoclinic system and that 

 the plane of symmetry lies across the needles. The mineral is there- 

 fore elongated parallel to the ortho-axis h. 



The data upon which the crystallographic calculations are based 

 were obtained on rather inferior crystals, which, however, were the 

 only ones available. The crystals were all warped in the zone of 

 elongation and also considerably striated in that direction. Fourteen 

 crystals were measured none of them exceeding 0.5 mm. in length. 

 For convenience they were mounted with the elongated zone vertical 

 and the resulting angular values, though in comparatively poor 

 agreement, were averaged. The data obtained with the two circle 

 goniometer are given in the table below. 



Measurements of crystal forms of chlorophoenicite 



