Sometimes, other factors come into play in the formation of minerals and these can produce the very large and very beautiful crystals which geologists, mineral collectors and several industries devotedly search for. One of these factors is as simple as the flow of water. As water from rain or rivers seeps into rock cracks, it begins to dissolve the minerals with which it comes in contact. In nature, however, this process takes a very long time. If the glass of salt-water is left on the counter for a long time, the water would eventually evaporate, leaving only the salt behind in the glass.
Nature performs the same way.
Certain minerals, for example, exist only in small quantities here and there, but when water dissolves the element or mineral, the solution then travels through the cracks in the rocks where it gets concentrated and eventually, large crystals form in the cracks themselves. This explains why many minerals are found in open cavities or vugs. The minerals found at Mont St. Hilaire and at the Francon Quarry were mainly formed by this very process of water flowing through cracks. The water, however, did not come only from rain or rivers. The magma itself held a large quantity of water.