Werner divided the opal into four sub-species, and Jameson has separated it into seven varieties. The principal divisions, however, may be classed as follows: precious or noble opal, presenting refulgent tints; fire opal, with fire-like reflections; girasole, with reddish reflections when exposed to the sunlight; common opal, translucent and without reflections; wood opal or petrified opal, possessing the characters of common opal; hyalite, clear and colorless as glass. There is another kind of opal which we have never seen, but which is described as the asteriated opal. We are not able to give a minute description of its appearance or draw a comparison between it and that of asteriated quartz, sapphire, or garnet. It is said to display great beams of light which undulate over its surface like the flashings of lightning piercing the storm cloud. The variety known as the moss opal sometimes displays in its interior dendritic crystallization of a dark substance resembling delicate mosses, ferns, or trees. And the gleam of the colored rays flashing amidst these miniature forests and groups of foliage often present charming effects. The grand characteristic which gives to the gem its value and renown is the wonderful play of the colored reflections which it displays, and which embrace all of the prismatic tints of the solar spectrum. As we view its vivid rainbow flashes when the gem is held in the sunlight, we must admit it to be the most magnificent of gems, and join with the Latin philosopher, who remarked that it was made up of the glories of the most precious stones. For as the light falls upon it in varied directions, its reflections recall the lively green of the emerald, or the tender blue of the sapphire, the rich yellow of the topaz, or the gorgeous red of the ruby.