DETERMINATION OF MINERALS. 391 



3. LUSTRE UNMETALLIC; B.B. ON COAL, OR LN CLOSED TUBE, ODOROUS 

 FUMES OF ARSENIC OR SULPHUR, OR REACTION FOR SULPHUR. 



ARSENATES, p. 189. On coal arsenical fumes. 

 CHALCANTHITE, p. 137. Bine; taste nauseous; astringent. 



Also Stromcyerite, Stannite, Bournonite give reactions for copper. 



4. COMPOUNDS OF LEAD. 



Yield B.B. on coal a dark lemon-yellow coating ; finally, with soda, 

 if not without, a globule (metallic and malleable) of lead is ob- 

 tained ; but by continued blowing with O.F. the lead all goes off in 

 fumes, leaving other more stable metals (silver, etc.) behind. Sul- 

 phurous, selenious and tellurous fumes easily obtained either on 

 coal or in an open tube from the sulphide, selenide, tellurides ; and 

 arsenical or antimonial fumes from ores containing arsenic or anti- 

 mony. None have taste. 



1. LUSTRE METALLIC. 



GALENITE, p. 145. H.=2'5 ; G. =7*2-7-7 ; cleavage cubic eminent ; 

 lead-gray, streak same ; in open tube sulph. 



SELENIDE S, TELLURIDES, ANTIMONIAL and ARSEN- 

 ICAL SULPHIDES, page 149. 



2. LUSTRE UNMETALLIC ; NO ODOROUS FUMES, OR REACTION FOR 



SULPHUR. 



MINIUM, p. 149. Bright red, streak same. 



CROCOITE, p. 150. Monoclinic ; bright red, streak orange-yellow ; 



B.B. with salt of phosphorus emerald-green bead. 

 PYROMORPHITE, p. 151. Hexagonal ; bright green to brown, 



rarely orange-yellow ; streak white. B.B. fuses easily, coloring 



flame bluish-green. 

 CERUSSITE, p. 152. Trimetric, often in twins; H.=3-3-5; 



G. =6-4-6 8; white, gyh ; lustre adamantine; often tarnished to 



grayish metallic adamantine. Effervesces in dilute nitric acid. 



3. UNMETALLIC ; REACTION FOR SULPHUR. 



ANGLE SITE, page 150. Trimetric ; white, gyh ; fuses in flame of 

 candle ; B.B. reaction for sulphur ; no effervescence with acids. 



5. COMPOUNDS OF TIN. 



CASSITERITE, p. 160. H.=6-7 ; G.=64-7-l ; brown, gyh, ywh, 

 black ; B.B. infusible ; on coal with soda a globule of tin, yield 

 no fumes. 



Stannite, p. 158. A copper, iron, and tin sulphide, does not give 

 B.B. a metallic malleable globule. 



