Crystal is a very trendy two font system that could be layered to give You multiple possibilities in designing. When You use it with gradient it gives a faceted 3-D effect. What is more it can be outlined that gives an additional industrial look.
Both fonts contains the same metricts so using them is so simple-just copy & paste in place in different layers and then play with colors, gradients, outlines as You like ?
Crystal is great for headlines and logotypes.