COMPOUNDS OF FCTASSIUM AND SGDIUM. ps3 
Y., are other localities. A handsome fibrous variety occurs 
at Franktown, Huntingdon County, Pennsylvania. Sicily 
affords fine cr ystallizations associated with sulphur? 
The pale sky-blue tint, so common with the mineral, gave 
origin to the name celestite. 
Celestite is used in the arts for making the nitrate of 
strontia, which is employed for producing a red color in fire- 
works. 
Strontianite.—Strontium Carbonate. 
Trimetric.. JA 7=117° 19’. Cleavage parallel to J, near- 
ly perfect. Occurs also fibrous and granular, and sometimes 
im globular shapes with a radiated structure within. 
Color often a light tinge of green; also white, gray, and 
yellowish brown. Lustre vitreous, or somewhat resinous. 
Transparent to translucent. H.=3:5-4. G.=3°6-3°72. 
brittle. 
Composition. Sr O;C = Carbon dioxide 29°7, strontia 
70°3=100. A small part of the strontium is often replaced 
by calcium. B.B. swells, throws out little sprouts, but 
does not fuse. Cclors the flame bright red, and after heat- 
ing possesses an alkaline reaction. ‘Effervesces in cold di- 
Jute acid; sulphuric acid gives a precipitate of strontium 
sulphate. | 
ae Its effervescence with acids distinguishes it from 
minerals that are not carbonates; the color of the flame 
before the blowpipe, from witherite and all other carbon- 
ates ; calcium salts also give a red color to the flame, but 
the shade is yellowish, and less brilliant. 
Oés. Strontianite occurs in limestone at Scoharie, N. Y., 
in crystals, and also fibrous and massive; and in tei 
son County, N. Y., and Mifflin County, Penn. Strontian 
in Argyleshire, England, was the first locality known, and 
gave the name to the mineral and the metal strontium. It 
occurs there, with galenite, in stellated and fibrous groups 
and in crystals. 
@his mineral is used for preparing the strontium nitrate. 
POTASSIUM anp SODIUM. 
Potassium and sodium occur in nature in the state of 
chloride, sulphate, nitrate, and carbonate, and are constitu- 
ents in many silicates. 
