Every kind of sand can be made useful
Artisans who do big works, and who need to search for things made by nature to pursue their work, because nature does not want to sell its wares to its children, and in order to save the time they would spend grinding, pulverizing and artificially preparing their sand, look for sand from sandpits, which is not too fat from the soil, nor too arid and, consequently, without any binder effect. From deep in the sandpit, one can find some lumps and gravel that show the sand’s natural compaction; it is quite hard to break, with very small and fine grains, quite smooth between the fingers. And since it is found solely close to mountainous regions or arid lands, you cannot find any near every good town, where artisans live. Thus, if they can’t find any close to their home, they prefer to order some of this sand from afar, like Lyon, Venice or Paris, near the Sainte Chapelle, and similar areas, instead of preparing it themselves. Nonetheless, you can be assured that in all locations, you can make sand from the sandpit and will be good and will mold cleanly. Because the sand is coarse and dry, filter it through a sieve. If it is not fine enough, wash it. And when the water has settled a little, pour the soiled water into another pot. The coarse [grains] will quickly fall to the bottom of the first pot. But the sand from the troubled water pot, having settled, will be much finer. If this sand does not bind enough, dry crush it on the porphyry, thus making it impalpable, and it will bind as chalk does. If you wish you can reheat it, and straight after crush it and blend it with salts, or burned cloth, or felt, or paper ashes, or similar material.