The many semi-precious stones which have a quartz basis (such as the varieties of waxy or cryptocrystalline chalcedony which is largely quartz in a very minutely crystalline condition) are often even tougher than the clear crystallized quartz. Carnelian, agate, quartz cat's-eye, jasper (containing earthy impurities), and those materials in which quartz has more or less completely replaced other substances, such as silicified crocidolite, petrified wood, chrysocolla quartz, etc., are all nearly as hard and quite as tough as quartz itself, and they make admirable stones for inexpensive rings of the arts and crafts type. JADE. Jade, of the jadeite variety, which is rarer than the nephrite jade, and more highly regarded by the Chinese, is an exceedingly tough material. One can beat a chunk of the rough material with a hammer without making much impression upon it. It is also fairly hard, about as hard as quartz, and with the two properties of toughness and hardness it possesses excellent wearing qualities in any kind of mounting. True jade, whether jadeite or nephrite, deserves a larger use in inexpensive ornaments, as it may be had of very fine green color and it is inexpensive and durable. SOFTER STONES. Coming next to those minerals whose hardness is 6 or over, but less than 7, we have to consider jade of the nephrite variety, demantoid garnet ("olivine" of the trade), peridot (or chrysolite, or the olivine of the mineralogist), turquoise, moonstone, and opal. As has already been said of jadeite, the jade of the nephrite variety, while slightly less hard, is about as tough a mineral as one could expect to find. It can take care of itself in any situation. The demantoid garnet (the "olivine" of the trade) is so beautiful and brilliant a stone that it is a pity that it is so lacking in hardness. It will do very well for mounting in such jewels as scarf pins, lavallières, etc., where but little hard wear is met with, but it cannot be recommended for hard ring use. The peridot, too, is rather soft for ring use and will last much better in scarf pins or other mountings little subject to rubbing or to shocks. Turquoise, although rather soft, is fairly tough, as its waxy luster might make one suppose, and in addition, being an opaque stone, slight dulling or scratching hardly lessens its beauty. It may therefore be used in ring mountings. However, it should be suggested that most turquoise is sufficiently porous to absorb grease, oil, or other liquids, and its color is frequently ruined thereby. Of course, such a change is far more likely to occur to a ring stone than to a turquoise mounted in some more protected situation.