When in Photoshop CS6 Extended 3D side of things, you need to add an Image Based Light in the environment properties. I just quickly googled a gold cloth. Then remember to set the Reflection on all sides, extrusions and bevels. Then to make it shine more, click on the text layer (still within the 3D workspace) and set Shape Preset to what you want. I used a Bevel because I could then trace around the letters with the Pen-tool on this bevel so I could inlay the diamonds using the save selections to make a mask so as only to show the diamonds in the middle of the letter.
This one above took about 5 minutes, I didn't let it finish rendering because you can see roughly how it will look. Just make sure you pick a really good 'Gold' texture and maybe a better diamond texture too. It is possible and with a little more time you could certainly reproduce the image in your OP.