The subject of this article is, as its name sets forth, a diamond of a yellow hue. After the Orloff it is the largest cut diamond in Europe, weighing one hundred and thirty-nine and a half carats. Tavernier, who first mentions it, says "it has a tinge of yellow which is a pity." King declares, "on the highest authority," which he does not further particularize, that this tinge is a very strong one, almost destroying its brilliancy. Yellow diamonds are not necessarily devoid of brilliancy, as we can bear witness from personal knowledge. There was recently offered for sale at a public auction in London a very large specimen known as the Orange Diamond, of one hundred and ten carats weight, which we carefully examined. The circumstances were decidedly adverse to the beauty of a diamond, for it was in the half-light of a London fog that we saw it, yet the stone seemed literally to shoot tongues of yellow fire from its facets. It was a round brilliant, and being set in a circle of about a score of white diamonds its tawny complexion was shown to admirable advantage. The jewel was supported on a delicate spring which vibrated with each step upon the floor, so that there was a constant coruscation of light around it. It is difficult to establish the early history of the Austrian Yellow. Tavernier saw it in Florence somewhere about 1642, but he does not say whence it came. Its appearance proves it to be an Indian-cut rose, but that does not help us much with regard to its private wanderings in Europe. A good authority on diamonds, de Laet, who flourished shortly before Tavernier's time, declared that the largest diamond then known weighed seventy carats, which would clearly indicate that he knew nothing about the much larger yellow diamond. Tradition relates that it was bought for a few pence in the market at Florence, under the impression that it was a piece of glass! If this is so, one would be glad of some particulars of the moment when the happy possessor found out his mistake. [Illustration: THE AUSTRIAN YELLOW--TOP AND SIDE.] Tavernier says that "the Grand Duke (of Tuscany) did him the honor to show him the diamond several times." He made a drawing of it, as he did of nearly all the large diamonds he saw, and his estimation of its value is two millions of livres (about four hundred thousand dollars)--a low price considering the size of the stone; but no doubt its yellow tinge had something to say to it. The Grand Duke of Tavernier's time was Ferdinand II., who reigned from 1621 to 1670--a man of considerable enlightenment, a protector of Galileo and an encourager of literature.