Had the lapidaries adopted the form of the Sancy, that is, the shape of the almond, with small facets all over it, a far greater brilliancy would have been obtained. Such is the opinion of Babinet and other connoisseurs, who are able to judge on this subject. The Koh-i-noor, before cutting, was submitted by Prince Albert to the examination of several eminent men, amongst whom was Sir David Brewster; and a variety of opinions were expressed upon the subject. It is generally believed that ideas of fashion directed the shape of the stone to be adopted; and that if its form had been left to Coster, the model of the brilliolette would have been copied, and but little of the stone sacrificed in the cutting. However, it is too late to lament the accident or the error; but we hope that the experience acquired will preserve other specimens for the admiration of art, although it availed nought in the case of the Star of the South, another stone admirably adapted for the exhibition of the beauty of the brilliolette model. This form, with numerous small facets, in both instances would have given more luminous points, and therefore produced more splendid effects. Babinet properly exclaims against the mode of cutting the large gems with large facets, as thereby much of the glory of the gem is lost. Had the Regent, even, been cut with smaller and more numerous facets, its splendors would have been greater. As we have previously stated, the most vivid play of light and color is exhibited in diamonds of about ten karats or less; we may, perhaps, attribute the difference to the violation of some law in optics, as well as to the difference in the laminæ or substance of the larger stones. Babinet, in defence of his remarks on this interesting subject, states that the beautiful rainbow hues are produced by the light entering the upper surfaces of the gem, and, being reflected backwards from the bottom surfaces, is then refracted, after traversing the side facets. The white light is then decomposed into every variety of hue, the perfection of which depends upon the condition of reflection and refraction. If the facets are too large and the light too voluminous there is danger of neutralization of these colors, and that white light be reproduced.