132 



DESCRIPTION OF THE DICHROIT. 



Where found. 



Not y«t ana* 

 lys«d. 



endued with a particular property, the knowledge of which 

 may be interesting perhaps to those philosophers, who study 

 the course of light through crystallized mediums. 



This mineral was found at Cape de Gattes, in Spain. It 

 was already known to the inhabitants of the country, and 

 the lapidaries of Carthagena, when Mr, Launoi, a dealer 

 in minerals, visited the place about twenty years ago, and 

 brought away some specimens, which have been sold, part 

 in France, and part in Germany. Most of these specimens 

 being badly defined, they added to collections a rarity, of 

 which science took no account. 



Being at Cape de Gattes a few years ago, I was fortunate 

 enough to meet with some pieces of the mineral in question, 

 all the essential characters of which were sufficiently de- 

 cided, and indicated a new species. I pur[K)sed to give a 

 description of it, as soon as I had analysed it ; but not yet 

 having had an opportunity of doing this, I ana induced to 

 Msiuloned bv publish my mineralogical observations on it, particularly as 

 writers. * some ioreign mineralogists have been beforehand with me. 

 Mr. Reuss, in the last volume of his treatise published in 

 1806, announces, that Werner has made a new species of 

 the substance from Cape de Gattes, by the name of 7/oHih; 

 that he has ranged it next the cat's-eye, and divided it into 

 three varieties, the vitreous, porphyritic, and common. Mr. 

 Karsten, adopting Werner's opinion, in his Mineralogical 

 Tables for 1808, has placed the yolith between the lazulite 

 and andalousite of Delametherie, and gives the following 

 description of it. 



*' This mineral is found of a deep lavender blue, in mass 

 or disseminated ; of a feeble lustre, verging from brilliant 

 to shining; with an uneven fracture, the fragments of which 

 are indeterminate, and with very acute edges j the separate 

 pieces are indistinct, and large grained. It is hard, brittle, 

 opake, and moderately heavy. It is found at Cape de Gattes 

 in Spain, associated with lithoraarge, qusirtz, and crystallized 

 almandine.'* 



It is difficult to find in this description the characters, 

 that induced Werner and Karsten to make a particular spe- 

 cies of the mineral in question, for it is equally applicable 



to 



Karsten's de- 

 tcriptien. 



