66 Practical Remarks on Gems. 



emery paper ; it is also used extensively for the polishing of cut- 

 lery, and even of some of the gems. It occurs in long six-sided 

 crystals, and in other forms in which the original crystals are so 

 abraded that their form cannot be distinguished ; in color it is 

 very dull, sometimes of an indefinable brown, green, red and 

 gray. 



10. Hypersthene, is the very opposite of corundum in consis- 

 tency, being as soft as the other is hard ; neither is it so useful, 

 though it is said sometimes to have figured in jewelry. It must 

 have made a very uninteresting appearance, as it bears but an in- 

 different polish. Its color is greenish black or brown; it is very 

 abundant on the banks of the Brandy wine, although of a very poor 

 kind ; but I have just seen some beautiful specimens from Massa- 

 chusetts. Although it appears to be in some repute with the 

 French, for jewelry, it is almost unknown to North American 

 jewellers. 



11. Red Oxide of Titanimn, is used by the dentists to impart 

 a tinge of color to their porcelain or incorruptible teeth which ren- 

 ders them more natural in their appearance. The color of this 

 is a copper red, approaching to brown, of metallic lustre, and when 

 found together with quartz, its appearance is very beautiful, 

 sometimes passing through the crystals in minute hair-like fibres.* 



12. Sphene, (Calcareous Oxide of Titanium.) Is but a vari- 

 ety of the preceding, and embraces such a range of form and color 

 as to render it difficult of recognition, except to those well versed 

 in the study. It is of a lustre less metallic than the above ; it is 

 opake and much harder ; it may easily be mistaken for the brown 

 garnet, which however is of greater tenacity and different struc- 

 ture. 



13. Spiu,elle. In color it is either red, brown or black with all 

 their intermediate shades and modifications ; it is found in granu- 

 lar and angular fragments, and octahedral crystals ; those of a 

 crimson color are much used in fine jewelry under the name of 

 spineile ruby, as also the rose-red or pink, which is styled the Ba- 

 las ruby; that of a violet color, closely resembles the Almandine 

 garnet, and is known as the Almandine ruby. There are other 

 varieties, such as the orangine or rubicelle. 



* The rulite of Middletown, in Connecticut, forms a most beautiful gem. It 

 has recently been brought out by Prof. C. U. Shepard, from London, polished and 

 set, and almost rivals the ruby. — Eds. 



