The question of what exactly constitutes marital property is one that family courts continue to wrestle with on a daily basis. For the most part, however, marital property is considered that which was earned or acquired during the marriage - unless you agree otherwise. Separate property is that which belongs to only one spouse, either because it was owned before the marriage, received as a gift during the marriage, was an inheritance or personal injury award or was acquired in one spouse's name and never used for the benefit of the other.
However, these rules aren't without exception, and one of those is the transmutation of non-marital property. Those filing for a divorce in Gary should educate themselves on this issue, particularly if they own a small business.