Crystal button Learning

After studying the crystal button, I found that there are several ways to download the style of the crystal button, which is both good and simple. However, I like the effect that I often see, but the style does not:

Find a simplified tutorial.

Http://www.blueidea.com/tech/graph/2006/3154.asp

Its core is the figure:

I used only one gradient to achieve this effect:

The key point is to gradient a white layer and control the transparency. The upper half is basically 50, and the lower half is from transparent to 50%.