Natural History. 219 



been induced to change the name of the mineral which I have 

 described, and to request you to give it circulation through the 

 medium of your Journal. The name having been suggested from 

 the powdery form in which this mineral has alone yet been found, 

 the Greeii word xovk, as applied generally to powder, may as 

 easily be used in compounding the term Konilite, ,It is not 

 cacophonous, and answers the purpose of describing the most 

 remarkable character of this mineral ; while it avoids any colli- 

 sion with the term to which I have alluded. 



3. Native Oxide of Chrome. — A new Mineral. — The com- 

 binations of this metal with two others, namely, lead and 

 iron, under different forms, have for some time found a 

 place in our catalogues of minerals. A place must now 

 also be made for Chrome itself, in that division of mineralo- 

 gical systems which is allotted to the metals. I am not aware 

 at least, that the oxide of chrome has yet been found by any 

 one in a native state ; certainly it has not been enumerated in 

 any system of Mineralogy. 



I have recently discovered it here in Shetland, in the island of 

 Unst. It is found in cavities in the chromate of iron, which 

 abounds in this island, so as, for the space of many miles, to 

 be scattered over the surface of the ground, and even to be 

 used in common with the loose stones which it accompanies 

 in the building of dykes. 



This oxide is easily recognised by its beautiful green colour, 

 and does not seem to differ from the green oxide produced in 

 our laboratories by the action of heat. In some places it is 

 merely diffused through the fissures of the ore ; in others it 

 occupies cavities resembling those of the amygdaloids. It is 

 sometimes found in a powdery form ; but at others it is com- 

 pacted into a solid substance, bearing the marks of a crystal- 

 line structure, and somewhat translucent. Although it appears 

 to be in abundance, when the specimens that contain it are 

 broken, that effect is only the consequence of the brilliancy and 

 contrast of its colour with the black and dark grey of the sur- 

 rounding chromate of iron. It would be very difficult to collect 

 many grains of it in a separate state from any of the fragments 

 of the black ore which I examined. 



The green oxide is accompanied by a yellow oxide of chrome, 

 in cavities generally distinct from it, but sometimes intermixed, 

 and in somewhat less abundance. This latter is more generally 

 in the form of powder than the green. As the green oxide of 

 chrome changes to yellow by heating it, M. Vauquelin 

 appears to think that these are distinct oxides ; but this point 

 does not seem to have as yet been very satisfactorily examined. 

 For the present purposes, it will, at any rate, be more conve- 

 nient to consider them merely as varieties of one mineral 



