Book V about lodestone, hematite, geodes, hematite, selenite, lapis secularum, asbestos, mica

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	BOOK V 95 it occurs in thick beds. In Livonia they make lamps of the very thin beds since they are not affected by fire. Today chemists mix the silver colored mineral with copper and other materials and make it so white that it resembles silver. Potters sprinkle this mineral on their jars to give them a silvery luster. They make table tops out of the silver-lead colored mineral that occurs in thick beds. These can be cleansed by both water and fire when soiled. Mica is similar in color to magnetis but has dissimilar qualities. It is the color of silver but is destroyed by fire. It occurs in stones, marbles and sands and having originated in these it cannot be separated. Our miners sometimes call it by a name signifying its luster¹¹ and at times by a name derived from the names feles and argentum⁾¹²Some call it magnetis.¹³ Just as mica is the color of silver, ammochrysos (phlogopite) is the color of gold. The sand is more the color of gold than the solid mineral, hence the name and not as Pliny writes because it resembles sand mixed with gold. Our miners call this mineral by a name derived from the words feles and aurum^u although it contains no gold. The golden powder that writers use instead of sand is made from it. A similar mineral is that which the miners call armatura (slickenside) because it polishes iron and resembles copper. However, it contains neither of these metals, in fact not even a trace of any metal can be produced from it. From its appearance it might have been the result of an unsuccessful attempt on the part of nature to make a metal. A stone that is clothed with this "armour" might be called hoplites, from the Greek. A cleavable stone is often so "armoured" and sometimes one side of a vein, for six feet or more, may shine like polished iron.¹⁵ Similarly ammonis cornu and other things are "armoured" but the "armour" of these is seen to be made, as a rule, from polished gold or brass, as I shall mention later.¹⁶ ¹¹ Glimmer. ¹² Katzensilber. ¹³ It would appear that magnetis and mica were distinguished primarily by mode of occurrence, the latter occurring in veins and hence consumed when the ores were smelted. It should be noted that Agricola distinguished talc and mica. The following description of mica is given in Bermannus, p. 454, Ancon. ". . . and a third mineral is white and sparkles in this rock like stars. Bermannus. "It is as you say and I believe that this is the mineral the Latins called mica and the German miners mica and 'cat's silver' or in their language 'katzensilber.' It is called silver because it is so similar in color to that metal that it often deceives boys and people who do not know about mines. The term 'cat' is used either because of the similarity of this mineral to the shine of a cat's eye at night or because they wish to compare it to the uselessness and worthlessness of a cat's voice. Nothing valuable is ever obtained from this mineral when it is smelted since it is entirely consumed in the fire." ¹⁴ Katzengold. ¹⁵ Agricola is describing a slickenside or wall of a fault that has been polished by movement. Slickensides often have a high luster and are common in shales that have been folded. ¹⁶ Ammonis cornu is an ammonite which here has been replaced by pyrite or marcasite.

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