Astrology is not a simple system, so don't turn to it if you want a clear-cut answer about what stone to call your own. Instead, you should consult the stars if you want to explore your range of options. In the same way that you can research your planetary signs and determine which ones speak to you, so, too, can you find the right birthstone for your personality— and your style.
The most common astrological system for birthstones is similar to the birth month system that you're already familiar with: