IRON MINERALS 



Pyrosmalite, II 7 (lM'.('l)i I'.-.Mn i 4 (SiO 4 ) 4 ; Oliv< - 

 to brown: n. basal; II. i Lfi III 



ASTROPHYLLITE, K.N.-i.H , .' I '. -.Mn.Mg.Ca). 



(SiO 4 ) 4 ; Bronze to golden-yellow: CI. pinacoidal 

 H. 3; G. 3.35; F. 3; IV. 



J. Show- n<> maniiain-r. 



LEPIDOMELANE, (K.H) 2 Fe" 2 (Fe.AI) 2 (Si0 4 ) 3 ; Hi:u-k 



to greenish black; Cl. basal; H. 3; G. 3.1: 



4.5-5; V. 

 ANDRADITE, Ca 3 Fc.>(SiO 4 ) 3 ; Wine, yellowish, given, 



brown; H. 7 ; G. 3.85 ; F. 3.5 ; I; p. 444. 

 Stilpnomelane, H 6 (Fe.Mg)2(Fe.Al) 2 Si 6 Oi8 ; Greenish to 



yellowish bronze; H.3; G. 2.75; F.4.5; Foliated. 

 Hisingerite, H, Fe, Fe, Mg, Si, O?; Black to brown- 



ish black ; H. 3 ; 2.75 ; F. Difficult ; Amorphous. 

 Chloropal, H 6 Fe 2 (SiO 4 )3.2 H,,O ; White, olive, blackish, 



yellowish green; H. 2.5-3; G. 1.87; F. Difficult. 



Amorphous. 



E. Insoluble or only slightly attacked by HCl. 

 1. Yields little or no water. 



a. In S. Ph. an emerald green bead (chromium). 

 CHROMITE, FeCr 2 O 4 ; Brownish black ; H. 7.5-8: 



G. 4.45 ; Inf. ; I ; p. 376. 



b. The S. Ph. bead reduced with tin on coal, then dissolved 



in dilute HCI. shows tungsten. $ It, p. 587. 

 WOLFRAMITE, (Mn.Fe)WO 4 ; Brown to black 

 Cl. pinacoidal; H. 5-5.5; G.7.35; F.4; V; p. oil' 



c. Fuses with intumescence and colors the flame yellow 



(sodium). 

 ARFVEDSONITE, (Fe.Na2.Ca) 4 (SiO3) 4 .Fe 2 (AI.Fe)j- 



Si,O 12 ; Black ; Cl. prismatic; H. 6 ; G. 3.1 



F. 3.5; V; p. 419. 

 Crocidolite, XaFe(SiO 3 ) 2 (Fe.Mg.Ca)Si03 ; Laveml, . 



blue; H. 6-6.5; G. 3.43; F. 3.5 ; Fibrou>. 

 Riebeckite, 2 NaFe(SiO 3 ) 2 .(Fe.Ca)SiO 3 ; Black: Cl 



prismatic; H. 6-6.5; G. 3.43; F. 3; V. 

 jEnigmatite, (Fe.Mn)(Fe.AI).Xa, (Ti.Si)O?; Black, 



Cl. prismatic; H. 6; G. 3.75; F. 3 ; VI. 



d. Fuses quietly, or with difficulty. 



ALMANDITE. Fe 3 Al 2 (Si() 4 )3 ; Deep to brownish red . 

 H. 7-7.5; G. 4.15; F. 3 ; I; p. 411 



