Gems Notes and Extracts Augusto Castellani, Mrs. John Brogden 1871

do not think itunlikelyBOORT. 47that Nero's emerald was anaquamarina cut for the purpose of a magnifying glass.In corroboration of the above, we bring to the notice ofthe reader the fact that Nicola de Cusa, Bishop ofBrixen, who died in1454, gave the name of Beryllusto one of his works for this reason, that " by means ofits assistance, people could understand things otherwiseincomprehensible ;" and in the second chapter heexpressly says : " The beryl is a bright, transparent,colourless stone, to which a concave or convex form isgiven by art, and by means of which whoever looksthrough it sees things otherwise invisible to thenaked eye."XYI.BOORT (KNOTTY DIAMOND).THIS particular species of adamantine carbon, whichseems placed by nature between crystallized carbon andthe pure diamond, bears a name of unknown etymology,but certainly of Dutch origin.Most frequently it is of spherical form, and its crystallizationis so irregular that it resembles the mostcomplicated knots in certain woods.It is a mixture of molecules without order or continuity,and these, adhering solely bythe force ofcohesion, are the cause of its wonderful hardness. Ithas not any regular cleavage.The boort is externally more roughthan some