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

AGATE. 23the cutting discovers circular bands of very smalldiameter, arranged with regularity round one circularspot. These circles are frequently so perfect that theyappear to be traced by the compass, and consist of twoor three, seldom of a greater number. The first roundis white ;the second, black, green, red, blue or yellow ;the most rare are those whose circles are at equaldistance from the centre.The tree, or dendrijica, agate, from the Greek So/Spov,a tree, is that in which the material being formed insuccessive strata, it has allowed access between thestrata to metallic solutions, which, under the pressureof the and air, by the solidification of crystals, remainthere in a metallic state after evaporation.It is called tree agate when the enclosed pieces representtrees, and muscosa when the pattern resemblesflies :very seldom are these two phenomena representedtogether on one piece. Agates are found containingimpressions of different plants, and of what appeargroups of herbs, bushes of box tree, and ramificationsof various sorts. The tree agate of the East is superiorto that of Europe ; the beautiful polish which it takes,and its natural brightness, contrast in a marvellousmanner with the dark-coloured ramifications.Whenthe colour of the plants is red, the agates are morevalued, because more rare.Figured agates are greatlyadmired for the form oftheir spots.Towards the close of the last centurythey were much in demand, and brought a high price,whence they were eagerly sought for, and perhaps