This morning at midnight, my parents finished the prosperity spell that was purchased in a round-about way from The Fey Dragon back in Oswego. The way it works is that Mary's recipe of herbs and magic mixes with whiskey and gets put on the windowsill nearest to the door which money would normally enter the house. There were words to be said and intent to be focused on -- and we had Dad say the words, since he is the one who does work the hardest at making money.The idea here seems to be that what was given in the acquiring of the spell jar would be returned when the need is greatest.
Part of the magic would have to be believing in the symbols. The physical jar spell in our house should be enough to help my parents visualize the results they so desperately need now. Sometimes for others, such measures are not needed. Sometimes the symbols are mental and a physical representations are unnecessary. For instance, as we read books -- we pick up symbols by visualization. We see the scene in our heads by way of the words we read. It never has to be the same as another person's scene, which is the beauty of it.
With magic, the more personal the representations are, the easier it is to invoke the mind frame needed to complete the spell. It is perfectly okay to use things like candles, spell parchment, gemstones, and other things. It's also fine to not use a single thing. I'm personally a fan of gemstones for other reasons than just symbolism. It is true that certain things contain specific energies that can be used. But even still, that is symbolic.