Which statement is true for all minerals? A. They have a crystalline structure. B. They contain useful metals. C. They are made of silicon and oxygen. D. They are too hard to be scratched with a nail.
c
option A is the correct answer
Minerals are naturally occurring, crystalline solid substances, of inorganic origin, with specific (but not necessarily fixed) chemical compositions. Examining this multi-part definition sequentially will allow us to understand the role of minerals in geology more clearly. First, minerals are naturally occurring. Thus, the products of industrial or commercial processes are not considered true minerals, no matter how well they fit the rest of the definition. Industrially produced minerals such as synthetic rubys or sapphires are readily recognized because of their purity of chemical composition. Nature is considerably more messy than a laboratory. Second, minerals are solid substances with a crystalline structure. To be crystalline means that the atoms within the solid are arranged in a geometric pattern that is unique to that mineral. Thus, altering that structure in any way results in the creation of a new mineral. Additionally, substances formed from the other phases of matter, liquid and gas, are not minerals. For that reason, water ice from a glacier is a mineral, while liquid water, steam, and ice cubes are not.
A) False - Opal and pearl are minerals but not crystalline struct. C) False - Non-silicate minerals such as Galena do not contain silicon or oxygen. Most mineralogists recognize ten or so major non-silicate groups. D) Really..?? So, Guess the answer is...
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