240 DESCRIPTIVE MINERALOGY. 



Its solubility and inferior hardness will serve to distinguish apatite from clirysoberyl, topaz, ■ 

 emerald, etc., which it sometimes resembles. It does not effervesce when treated with acids, 

 nor does it give out hydrofluoric acid, except in small quantities, when acted on by sulphuric 

 acid. By these negative characters, it can be distinguished from the carbonate of lime and 

 fluor spar. Wagnerite is soluble in dilute sulphuric acid, which is not the case with apatite. 



Composition. Phosphoric acid 44.32, lime 55.66 (Rose). It usually contains also minute 

 proportions of fluoric and muriatic acids. 



Geological Situation. Apatite occurs in gneiss, granite, and white limestone. The 

 fibrous variety, Eupyrchroite of Emmons, is found in limestone in the town of Crown-Point, 

 Essex county. 



localities. 



Essex County. According to Dr. Emmons, this mineral occurs at Long pond, associated 

 with garnet and idocrase ; and it has also been found in brown six-sided prisms, generally half 

 an inch long, in granular oxide of iron.* 



The magnetic iron ore at the Sanford mine in East-Moriah, is often thickly studded with 

 small six-sided prisms of apatite, with imperfect terminations. The same mineral is also 

 found, but more sparingly disseminated, in the ore of the Hall mine, near the preceding. 

 This, although an interesting mineral, is one of the most troublesome associates of iron ore 

 (see page 15). 



About a mile south of Hammondsville, in the town of Crown-Point, there is found a fibrous 

 variety of this mineral, which was described by Dr. Emmons under the name Eupijrchroite. 

 The colour is pale malachite green, passing into greenish white, and sometimes brownish. 

 Structure indistinctly fibrous in the thin mammillated layers, which are arranged like those 

 of green malachite. Dull and opaque. Hardness 4.0. Specific gravity 3. 06.t 



According to my analysis, the composition of this mineral is as follows : 



Phosphate of lime, _^ 92 . 85 



Oxide of iron, with a little alumina, 5. 20 



Silica (foreign), . 0.50 



Water, 1.50 



Fluoric acid, traces. 



The oxide of iron, silica and alumina, are undoubtedly accidental impurities, as it is almost 

 impossible to obtain masses which are entirely free from the accompanying rock. The pre- 

 sence of fluoric acid can be shown, by reducing the mineral to powder, and then mixing it 

 with sulphuric acid in a platinum crucible. Upon covering the crucible with a plate of glass, 

 and applying a gentle heat, the glass is soon corroded. In tliis way, I have also detected that 

 acid in the crystalhzed phosphate of lime of Orange and St. Lawrence counties. 



* Morton. Clmveland's Mineralogy. f Emmons. New-York Geological Reports, 1838. 



