Another pattern, called the brilliolette, shows the beautiful qualities of the gem to great advantage. It is formed like two rose diamonds joined together at the base; or may be flattened and elongated like the almond, and faceted all over with small facets. This is the form of the Sancy, and should have been given to the Koh-i-noor and the Star of the South. The Austrian yellow diamond is of this pattern, and was probably cut in India, but when and where is still a mystery. And it is thought that the famous twelve Mazarins were also cut after this shape. The star pattern, which was invented by Caire, is but little used at the present time. CHAPTER XIII. TESTING OF THE DIAMOND, ETC. The testing of the diamond is generally an easy matter to the expert, but the merchant and the amateur are often unable to decide quickly concerning the character of a gem that may be offered to them. The learned Abbé Haüy was often called in consultation upon matters of this kind, and even appeared in court as an expert of diamonds. Fortunately, the methods of ascertaining the diamond beyond a doubt are now so easy and numerous that few attempts are made like those of the last century, when white topazes and zircons were sold or substituted for diamonds. We may be permitted to say that the first and surest test of the gem is that of hardness, and that the diamond scratches all other substances with ease. The application of this test is not always made with facility, but a little practice with a rough crystal of diamond will soon enable the experimenter to perform it satisfactorily. In performing the test for hardness for all gems it is well to be provided with a fine English file, and splinters of quartz, topaz, and sapphire. The file, adroitly applied, will detect the character of gems below the quartz in hardness, and the splinters above mentioned will determine all others but the diamond. In applying these tests, it is well to touch the middle of a facet, if the gem be polished, and remember that the edges of many of the gems are very brittle. The diamond, for instance, although it is so very hard when its surface is directly tested, yet its thin edges, when cut into a gem, are broken down with the greatest ease; therefore the test of hardness should be applied to the polished face of the stone.