This is the best tutorial I have seen for making Diamond Text from Scratch....
We'll begin this tutorial, by creating a new canvas at a size of your choice with a dark background. I will be using white for illustration purposes. I used "ValleyGrrrlNF" with a size of 87 pixels. Type "Diamonds".
You will now have to make a diamond. To make a diamond you will need to
go here. Then learn to create a pattern by
going here. Or download the diamond effect
here. Once opened, Simply open you "Styles Palette" and apply the style to your Text.
Now that you have your text, you can now right click on the text layer and select, "Blending Options...". Go ahead and click on "Pattern "
Do not click OK yet... still more to do.
Now go ahead and click on "Gradient "
Click "OK" .
Now just simply add some twinkles to make it really glow and your done.
The Results!!!
Take this the do some 3D... should be good to go.