APOPHYLLITE. Apophyllite is a hydrous silicate of potassium and calcium which obtains its name from the Greek word APOPHULLIZO, to exfoliate, because it falls in leaves before the blowpipe. It is extremely soft, being from between 4 and 5 in Mohs’s scale. The stone is found in a variety of colours—milk-white, greyish, green, yellow, red, pink. It is seldom used by jewellers. The apophyllite is under the sign Taurus. AQUAMARINE. (See BERYL.) ASBESTOS. The word is derived from the Greek ASBESTOS, inconsumable, and is identified with the Amianthus (impollutible) of the ancients. It is a variety of hornblende, of a fine and fibrous texture, of which Marbodus wrote: _“Kindled once it no extinction knows But with eternal flame increasing glows. Hence with good cause the Greeks Asbestos name, Because once kindled nought can quench its flame.”_ The incombustibility and weak heat conducting qualities of asbestos render it extremely useful as a protection against fire. The ancients used it for the wicks of their temple lamps, and in order to preserve the ashes of the departed their dead bodies were laid on asbestos before being placed on the funeral pyre. Cloths of asbestos were thrown in the flames for the purpose of cleaning them. So fine and flaxy is the mineral that gloves have been made of it. Asbestos is under the zodiacal Gemini. AVENTURINE. Aventurine or goldstone is a quartz of a brownish, semi-transparent character, spangled with spots of golden-yellow mica. This stone is identified with the stone called by Pliny the “Sandaresus”—“of stars of gold gleaming from within.” The name Aventurine (_per adventura_, by accident), arose, it is said, from an accident in a Venetian glass factory, where a workman found that eight parts of ground glass, one part protoxide of copper and two parts of oxide of iron well heated and allowed to cool slowly, produced the peculiar appearance admired in the real gem to even better effect. The aventurine variety of quartz is under the zodiacal Leo. AXINITE. The name Axinite is derived from the Greek AXINE, an axe, on account of the sharp and axe-like form of the crystals. The axinite is about the same degree of hardness as the Spodumene or the demantoid garnet (6.5 to 7). It is pyro-electric and highly vitreous. The colours vary between pearly-grey, clove, brown, honey-yellow, violet, plum-blue. The axinite is under the zodiacal Sagittarius. AZURITE. Azurite is a blue copper carbonate obtaining its name from its colour. It is kindred with malachite, from which it differs but slightly. Some mineralogists call it blue malachite. It is under the zodiacal Libra. CHAPTER XIII THE BERYL FAMILY