Some time ago a mineral was put into my hands by Mr Rose, the intelligent mineral dealer of this city, the nature of which was not known, although it had been conjectured to be a variety of Mesotype. Mr Rose obtained it from Count Vargas Bedemar of Copenhagen, who brought it from the Faroe Islands, and subsequently visited this country some years ago. A short chemical examination soon satisfied me that it differed entirely from mesotype; and having ascertained that it contained silica, lime, water, and potash, and no notable quantity of alumina, I was led to conjecture that it would prove to be a variety of apophyllite, although, in that view, it would have presented very remarkable deviations from the ordinary structure of that mineral.