Making Button

Height:150 Width:150 White Background.

File > New 

Shortcut Ctrl + N 

Create  a new layer. Layer > New > Layer

Shift + Ctrl + N

Choose elliptical marquee (M) .Hold the shift key down while drawing your circle.

Choose Gradient tool. (G)

Make sure you have Radial Gradient one selected.

Start from the top left corner and finish at the bottom right corner.

Select > Modify > Contract

Turn the selection with image 180

Edit >Transform > Rotate 180

Contract selection by 2. 

Select > Modify > Contract 

Turn the selection again by 280

Edit > Transform > Rotate 180

Image >Adjust > Hue/Saturation Check colorize.

Play with the values this till you get the color you like.