Finding compounds with B, Si, Ca, and Mg in differing amounts Not sure if my question is better suited to a software related group, but here goes: 

Is there a software program that lets you add differing amounts of elements, minerals, etc., then tells you what the items added might make?  Specifically, I am looking for information about what boron, silicon, calcium and magnesium together (no idea about amounts for each) would make.
This would be an exceedingly difficult problem.

My suggestion might be to use a database like the Crystallography Open Database and perform searches with the elements you indicate.

For example, the search interface ensures B, Ca, Mg, and Si are all in the compound. I get 141 matches.

It would be incredibly hard to predict compounds with arbitrary stoichiometry. There are several genetic algorithm search packages that let one attempt to find low-energy crystal structures given a formula, including:


XtalOpt
GASP
USPEX


This is, however, an incredibly active area of research. I'm not sure if any of these packages can handle arbitrary amounts of different elements, or how they would handle missing elements. (For example, the elements you describe could be found in various borosilicate minerals given that oxygen is also allowed.)