IRIDESCENT COPPER PYRITES. 



Protoxide of iron . , . 8-32 

 Protoxide of manganese . 0-33 

 Water . . . . . o-59 



99-46 



BB alone fuses with difficult}- at the 

 edges to a transparent blue glass: with 

 borax melts slowl}^ to a clear globule. 



Only partially soluble in acids. 

 _ Localities.— Ireland. The Island of Rath- 

 lin ; Dalkey, near the river Dodder, co. 

 Dublin. — Foreign. Cape de Gata, in Spain, 

 imbedded in granite. Uiordlersoak and Se 

 mitok in Greenland in Quartz. Distinctly 

 crystallized at Bodenmais in Bavaria {Pe- 

 liom). Tunaberg in Sweden. Finland at 

 Orijerfvi {Steinheilite), and Fahlun {Hard 

 Fahlunite). lolite is occasionally employed 

 as an ornamental stone. The transparent 

 variety found in small rolled masses in Cey- 

 lon, is the Sapphire d'eau of the jewellers. 

 It is of a clear white mingled with celestial 

 blue, formin<>: a sort of mixed colour when 

 viewed in different directions, in consequence 

 of its property of dichroism. 



Name. From 'sv, violet, and A/6W, stone, 

 in allusion to its bluish-violet colour when 

 viewed in one direction. 



Brit. Mus., Case 36. 



31. P. G. Horse-shoe Case, Nos. 1003, 

 1009. 



Ikidescent Copper Pyrites. See Pea- 

 cock Copper. 



31. P. G. Principal Floor, Wall-case 6 

 (British). 



Iridescent Quartz. See Iris. * 



lRiDosMiNE,iVec^e/-. Trid-osmium, Haiis- 

 mann. Iridium Osmte, Haiiy. Hexago- 

 nal ; rarely found crystallized in hexagonal 

 prisms Avith replaced basal edges ; generally 

 in small irregular flattened grains, whicli 

 are harder, heavier, and of a somewhat 

 paler steel-grey colour than Native Pla- 

 tinum, Lustre shining metallic. Opaque. 

 Brittle and difficultly malleable. H. 7. S.G. 

 21-118. (G.Rose.) 



Fig. 244. 



Comp. Osmide of iridium. 



Analysis, from Australia, by Deville 

 Dehray : 



Iridium .... 58-13 

 Rhodium . . . .3-04 

 Ruthenium .... 6'22 



IRITE. 



191 



Osmium 

 Copper . 



33-40 

 0-15 



100-00 

 BB infusible ; both alone and with fluxes. 

 Insoluble in acids. 



Localities. With platinum in the pro- 

 vince of Choco in South America; and in 

 the Ural Mountains of Siberia. Rather 

 abundant in the alluvial Gold of California, 

 occurring in small bright lead-coloured 

 scales, which are sometimes six-sided. 

 Canada, in the gold washings on the rivers 

 Du Loup and Des Plantes. Australia. 

 Borneo. 



For varieties, see Newjanskite and Sis- 



SERSKITE. 



Name. From Iris, a rainbow ; the solutions 

 of Iridium being or variegated colours. 

 Iridium is used for the nibs of pens, and is 

 worth £24 per ounce. 



Brit. Mus., Case 3. 



31. P. G. Principal Floor, Wall-case 23, 



Iris. The name applied by French 

 jewellers to a very limpid and transparent 

 variety of Rock Crystal, possessing the 

 property of reflecting" the prismatic colours 

 by means of natural flaws in the interior of 

 the stone. When cut in cabochon or 

 goutte de suif, it imitates Opal to a certain 

 extent, and the superb Iris ornaments worn 

 by the Empress Josephine frequentlv de- 

 ceived even persons skilled in such matters, 

 by their brilliancy and play of colours. 

 This stone is not made up at the present 

 day. Rock Crystal may be easily made into 

 Iris, either by a blow from a mallet, or bv 

 dropping it suddenly into boiling water, or 

 by heating and suddenly dropping it into 

 cold water; but in these cases the fissures 

 produced are on the outer part of the stone 

 instead of being in the interior, as is the case 

 in true Iris. (Barbot.) 



Irite, Hermann. Cubical : occurs in octa- 

 hedrons. Isomorphouswith Spinel, Magnetic 

 Iron, &c. Occurs in strongly lustrous black 

 scales, which are attracted bv the magnet. 

 Soft. S.G. 6 506. 



Comp. A compound of the peroxides of 

 iron and chromium, with the protoxides ol' 

 iridium and osmium, represented by the 



formula R R, or (ir, Os, Fe) (Ir, Os, Cr)2 0. 

 Analysis, by Hermami : 



Peroxide of iridium . . 62*86 



Protoxide of osmium . . 10*30 



Protoxide of iron . . . 12*50 



Peroxide of chromium . . 13*70 



Peroxide of manganese . trace 



99*36 



