and deepest azure, more than two inches long, and one inch broad. The
finest ruby among these gems is more treasured for its antiquity than
intrinsic value, it being the one worn at Cressy and Agincourt, by the
Black Prince and Henry V.: this is worn on the back cross, and the
sapphire on the front, of the imperial crown upon state occasions.

_Why are garnets often found of a reddish brown tinge?_

Because of the excess of oxide of iron which they contain; a small
proportion being sufficient to colour them entirely, without injuring
their play and splendour. In fact, the perfection of all gems depends
less on the quality of their component principles, than on their
complete solution and intimate combination. The alkalized earths, as
lime, magnesia, and still better, pot-ash, seem to intervene as
solvents, for alumina, completely dissolved, acquires, as we have shown
from Klaproth, a crystallization, of which, by itself, it is not
susceptible.

The garnet is found in Bohemia, Ceylon, and other countries; but the
chief mart formerly being Sirian, the capital of Pegu, the best are
often denominated Sirian garnets. The colour most esteemed is blood or
cherry red, mixed often, however, with blue, forming tints of crimson,
purple, and reddish violet; or orange red and hyacinth brown. The Sirian
garnet is of a violet colour, which, in some rare specimens, makes it
compete with the amethyst, from which it is to be discriminated by the
disadvantage of losing its brilliancy, and acquiring an orange tint by
candlelight. Distinct from all other garnets, it preserves its colour
unmixed with the common black tinge, unassisted by foil, even when
thick. _Course garnets_ are used as emery for polishing metals, and by
lapidaries. They are found in Ireland, in Norway, and many other