THE OPAL. l6l
an endless series of opals is obtained; but in commerce only three varieties are recognized—
The Oriental Opal. The Fire Opal. The Common Opal.
The oriental opal, called also the noble opal and the harlequin opal, shows
generally in its fire a triangular disposition very characteristic. It
exhibits flashes or flames of the most brilliant colours.
affection that the ancients entertained for this beautiful gem was
unbounded. The Roman senator Nonnius preferred exile to parting with a
brilliant opal the size of a filbert, which Mark Antony coveted.
A very beautiful opal, considered by the virtuosi of Vienna and Dresden as the third in rank of the beautiful opals of the world, is described by Jack-