CLASSIFICATION 



lOO' 



D. Gems of the Fourth Rank. 

 Hardness 4-7. Specific gravity 2-3 (with the exception of amber). Colour and lustre 

 are frequently prominent features. Not as a rule perfectly transparent ; often translucent, 

 or translucent at the edges only. Wide distribution. Value as a rule small. 



21. Quartz. 



A. Crystallised quartz. 



a. Eock-crystal. 



b. Amethyst. 



c. Common quartz. 



a. Prase. 

 0. Avanturine. 

 y. Cat's-eye. 

 S. Eose-quartz. 



B. Chalcedony. 



a. Chalcedony. 



b. Agate (with onyx). 



c. Carnelian. 



d. Plasma. 



e. Heliotrope. 



f. Jasper. 



g. Chrysoprase. 



C. Opal. 



a. Fire-opal. 



b. Semi-opal. 



c. Hydrophane. 



d. Cacholong. 



e. Jasper-opal. 



f. Common-opal. 



22. Felspar. 



a. Adularia. 



b. Amazon-stone. 



23. Labradorite. 



24. Obsidian. 



25. Lapis-lazuli. 



26. Haiiynite. 



27. Hypersthene. 



28. Diopside. 



29. Fluor-spar. 



30. Amber. 



E.- Gems of the Fifth Rank. 



Hardness and specific gravity very variable. Colour almost always dull. Never 

 transparent. Low degree of lustre. Value very insignificant, and usually dependent upon 

 the work bestowed on them. These stones, as well as many of the last group, are not 

 faceted, but worked by the ordinary lapidary in the large-stone-cutting works. 



31. Jet. 



32. Nephrite. 



33. Serpentine. 



34. Agalmatolite. 



35. Steatite. 



36. Pot-stone. 



37. Diallage. 



38. Bronzite. 



39. Bastite. 



40. Satin-spar (calcite and aragonite). 



41. Marble. 



42. Satin-spar (gypsum). 



43. Alabaster. 



44. Malachite. 



45. Iron-pyrites. 



46. Rhodochrosite. 



47. Haematite. 



48. Prehnite. 



49. ElsBolite. 



50. Natrolite. 



51. Lava. 



52. Quartz-breccia. 



53. Lepidolite. 



Among the stones enumerated above are a few such as marble, alabaster, &c., which 

 are never worked for personal ornaments, but only for other decorative objects ; these stones 

 will not be considered in the present book. On the other hand, there are certain stones 

 omitted from Kluge's list which will receive attention here, although they are but rarely 

 applied to the use of personal ornament. In the description which is now to follow, the 

 different precious stones are not arranged in classes, but are dealt with one after another in 

 the order of their relative value, combined to some extent with mineralogical characters. 

 Stones belonging to the larger families of minerals are placed in juxtaposition, although 

 individual members of each group may differ considerably in value. The following is a 

 tabular review of the precious stones here dealt with, and the order in which they are 

 taken. 



