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187 chapter xv y How to Recognize Silver Mines First, generally, silver mines can be found in lands with red or white earth, land without trees and with little grass. You should always look at the top of the knolls and hills, since this is where the veins of silver pop up in the same way that old walls follow straight lines, or how foundations are underground, or how a mountain top is made of many stones piled in a ring. If you find many stones together, always look for the largest or the one that is more or less in the middle of the mound. In prospecting a vara or braça, always following the vein, experience can be gained of the types of metals present. There are veins that contain five or six types of stone, which Castilians call metals . These veins are usually one braça, or four, three, two, or one palma wide. Mostly within the vein there is soil of various colors. Sometimes it is all compacted stone and is normally black and white like pebbles. When there is soil between the stone, both it and the stone contain silver. These veins usually occur in wild crags; from the surface of the earth to underneath it, they are always compacted. The stone is of various colors and distinct. It is vibrant white and black and similar to isinglass35 used to add sparkle to letters. It is the color of gold, yellow, blue, greenish, brown, the color of liver,36 orange, and tawny.37 Normally it has holes in it where the silver forms in lumps. Other stones are filled with silver, while still others have veins of silver in them. In these stones only, they know right away that they contain silver. However, only the most experienced will know or come to possess knowledge of the stones mentioned above. Also, at times a piece of black isinglass is found and is covered in silver. Normally one libra of this isinglass will yield two onças38 of silver. For the most part, there are no veins of silver without white or yellow isinglass, rough stones, or earth next to them. The Castilians call all these stones metals. Some give them these 188 Gold Mining names: metal cobriço is a very heavy green stone, salty to the taste and an astringent. It burns the lips with a taste of a mixture of antimony and acid. Metal polvorilha is a somewhat yellow stone and is superior to the stone mentioned above. Sometimes deep within it, it yields solid pieces of silver. First-quality metal negrilho is a black stone with glimmerings of large pieces of iron, and it is an inferior stone. It is mixed with a black metal of second quality with small, shiny bits of sand, and that of a third quality which is the type that, when powdered, has no shiny qualities. It is the best, and notice should be taken of it. Metal rosicler39 is a black stone similar to the metal negrilho, with more sand. It produces a dark powder without any shimmer. In order to determine if it is rosicler, pour water over it and use a knife or key as people do when grinding, and it forms a type of mud as if it were bleeding from having been stabbed. The more the mud is stirred, the stronger is the rose coloring. It is a very rich mineral and easy to extract. Where the water flows from the hills, all you need do is look for it. In a mud trough it becomes like clay, and it produces little stones in all the colors. Metal paco is also like the rosicler, and it is a stone that is almost brown, like a brown cloth or something darkened by smoke and very heavy. It would be very complex to list its attributes, qualities, and uses when it forms layers. It is used in a variety of ways depending on the types of pacos. However, the stone does not have a good taste when crushed and chewed, but it is a superior stone to use in casting at a foundry because it contains a lot of lead, which helps in casting. The metal and the negrilho are the most common found in the mines; their veins do not disappear, nor do they change. Where there is a lot of it, pacos stone will shift to negrilhos and negrilhos to pacos. Metal plomo...

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