298 Alger’s Localities of Rare Minerals, 
of a wax or honey-yellow color, have a waxy lustre, and the 
smallest individuals are translucent. They are brittle, break- 
ing with an uneven fracture, have none of the foliated structure 
: of Stilbite, and afford no indications of cleavage. Hardness 
superior to that of Stilbite, and equal to that of Chabasite. 
Their surfaces are roughened or pitted, so as to reflect no 
image by which they could be subjected to measurement by 
the goniometer. Before the blowpipe, a fragment of the 
mineral swells and intumesces slightly, like the Bohemian and 
Ferroe Chabasite, and fuses into an opaline, blebby bead ; at 
the mofhent of ignition, in the outer flame, it gives out a 
beautiful green phosphorescence, which I have also noticed, in 
a less degree, in the Phacolite from Ireland. It is soluble in 
hydrochloric acid. The crystals, at first sight, appear to be 
rounded, and to have no determinate form; but, on closer 
examination, some of the smaller and more isolated ones are 
found to be nearly perfect double six-sided pyramids, precisely 
similar to the Phacolite from Bohemia, differing from it only 
in color and lustre. I cannot doubt that, like that mineral, 
they are secondaries to a primary rhombohedron, probably of 
the same measurements, and are also identical with it in com- 
position. The absence of well defined cleavage is unfortunate, 
but this is a defect which applies equally to the foreign min- 
eral. Nor is the rhombohedral cleavage of ordinary Chabasite, 
of which Phacolite is by many supposed to be only a variety, 
by any means easily determined ; in fact, Sir David Bee 
has suggested, from optical investigations, whether the primary 
form of Chabasite be not a prism. ; 
Is Phacolite a variety of Chabasite, or distinct from it? 
Tamnau, of Berlin, in his very complete little essay on Chaba- 
sites, has given very good reasons for uniting the two; while 
Breithaupt has maintained them to be distinct. The primary 
rhombohedron of Phacolite, according to Breithaupt, 1$ Ton 
P, 94°, that of Chabasite P on P, 94° 24’. Phillips makes 
the last 94° 46’. The analyses of Anderson and Rammels- 
berg would seem, at first, to show a marked difference 1n their 
