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Book I Minerals color, taste, odor , physical properties of gemstones and minerals such as emeralds, diamonds, rubies, sapphires

Book I Minerals color, taste, odor , physical properties of gemstones and minerals such as emeralds, diamonds, rubies, sapphires Page of 251 Book II About different applications of earths (painting, medical) and their occurrences Text size:minus plus Restore normal size   Mail page  Print this page
20
DE NATURA FOSSILIUM
tained metallic particles a mixed earth when it is actually a composite earth. But it behooves one who teaches others to give exact names to everything.
An earth and a juice do not form a mixed mineral if the former absorbs the liquid, surrounds the congealed juice, or adheres to it. The juice can always be washed out and at times even removed by hand. But a stone and a juice can produce a mixed mineral when a solid is created from material of each one, even if sometimes if retains the appearance of one of them. Many mixed minerals form from an earth and a metal and even more from a stone and a metal. Several mixed minerals contain a stone, juice, and metal. Thus we see that there are four forms of mixed minerals which again, as genera, are divided into species.
When two simple substances form a mixed mineral they may be com­bined in equal or unequal proportions. When combined in equal propor­tions they form one genus and combined in unequal proportions they form two, since sometimes one substance predominates, sometimes the other. According to that reasoning three genera may be found which con­tain a metal and a stone, however, only one of these genera has been found that contains an earth and a metal, namely, the third genus which con­tains more metal than earth. I believe that the first genus with equal parts of metal and earth and the second with more earth than metal have never been found. Only the first and third genera of mixed minerals which con­tain a stone, congealed juice, and metal are found. This class of mixed minerals is formed from these simple things in such a manner that the mixture contains abundant metal and more congealed juice than stone. This refers to mass not weight since the mixture might have a greater mass of congealed juice than metal and yet the metal could have the greater weight.
Since the third genus is divided into three parts, there are six genera of mixed minerals and each of these contains many species. The first genus which forms from stone and congealed juice embraces Tusculum flint, Sa­bine stone, and many others. The second genus contains a metal and earth, the third has equal parts of stone and metal, the fourth is rich in metal, the fifth, with an abundance of stone embraces gold, silver, and copper ores. The sixth genus includes sulphurous pyrite and bituminous cadmia which contain other metals. The older Latin and Greek writers have not recognized the natures of many mixed minerals, or if they did, they have not described them sufficiently. They have called the forms of these either stones, such as pyrite, cadmia, and galena, or veins of gold, silver, and cop­per, since they did not distinguish between composite and mixed. I shall not say more now about these things but will take up the earths, both simple and mixed.
Book I Minerals color, taste, odor , physical properties of gemstones and minerals such as emeralds, diamonds, rubies, sapphires Page of 251 Book II About different applications of earths (painting, medical) and their occurrences
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