IRIS. The “Iris resplendent with the crystal’s sheen” which the “swarthy Arabs glean” is now known as Rainbow Quartz. The iridescence is produced by the reflection of light from the cracks in the stone. The same effect is produced if the crystal is first subjected to heat and then plunged quickly into cold water. The Iris obtained its name from the beautiful companion of Juno, who travelled on the rainbow with wings extended clothed in glorious colours, radiant lights around her head. She was the guide and helper of the souls of women released from their bodies. LAPIS ARMENUS, or Armenian Stone, is a copper carbonite used as a medicine against infection. It is related in Arab books that a solution of this substance will retain its power for 10 years. In the East copper has been long used as a safeguard against cholera, and it has been observed that workers in copper mines have enjoyed immunity from the disease. Dr. Richard Hughes notes the value of copper in Asiatic cholera, adding: “There is now abundant evidence of its efficacy both among the workers in the metal and in those who have worn a plate of it next the body during the prevalence of the epidemic.” The Lapis Armenus, like all copper compositions, is under the rulership of the planet Venus. LAPIDES FULMONIS. These Thunder stones which are believed to be formed by the lightning in the clouds (see Obsidian) are known by the peasants of Calabria as CUOGNI DI TRUONI. The traditional belief is that they are plunged by the lightning stroke six feet into the earth and that every time it thunders they are drawn one foot nearer the surface. After the sixth or seventh thunder storm it is said that the stones are raised to the surface. The peasants test them by suspending them above a fire, attached to a blue thread; if the thread does not burn the stone is adjudged a true thunder stone and is carefully treasured as a potent talisman against the lightning stroke. LAPIS MEMPHITICUS. This stone of Memphis is described as a sparkling round body of about the size of a hazel-nut. It is mentioned by Pliny as deadening the pain of surgical operations if taken in wine and water beforehand. If it be reduced to powder and applied, according to Dioscorides, as an ointment to that part of the body to which a surgeon was about to apply either fire or the knife, it produced insensibility to pain. This is an early instance of the recorded action of a local anaesthetic. LUZ or LUEZ. This is said to be a stone or indestructible bone in the human backbone. Dr. John Lightfoot, a great Hebraic scholar of the 17th century, details the following legend: