I am happy to hear of your interest. I'm not the best at writing tutorials but here it goes... ;\
For the Background
Create a new document sized 600 x 600 px
Run a Linear Gradient white to black with white on the top
Run Filter/Artistic/Pallet Knife (Stroke size 25, stroke detail 3, softness 0)
To add some color Image Adjustments/ Hue& Saturation/ Colorize and play with the Hue slider. I choose green to contrast with the red jewel.
For the Jewel
Use the Rectangular Marquee tool, Fixed sized 450 x 450 px
Fill the Marquee with the Linear Gradient called Silver going from the upper left corner to the lower right. Keep the Selection On!
Run Filter/Distort/Wave(5 generators, type Square, wave length 10 min 324 max, amplitude 05 min 404 max, scale 100% and 100%, undefined areas set to wrap around)
Copy Layer
Edit/Transform/ Rotate 45 degrees, Set layer to Multiply. Link and Merge with the Copied Layer.
Copy Layer.
Edit/Transform/Rotate 22.5 degrees. Set Layer to Overlay.
Switch to the Elliptical Marquee but keep size fixed at 450 x 450 px.
Center Marquee. Inverse the Selection and Delete. Do the same for the layer below so you should have two 450 x 450 px circles. Inverse the Selection.
To add color
Add a new layer and fill the Selection with a color of your choice, set layer to Vivid Light.
Copy layer for more intense color if you wish.
For shading
With the selection still active, add a new layer and fill the selection with a Radial Gradient black to white so you end up with a "black spot" at the top. Set layer to Vivid Light but adjust the fill to 42%.
Copy the layer but switch the layer to Overlay. Fill is still at 42%
To define edges
With the Selection still on, add a new layer and fill marquee with white. Select black and Stroke the selection with a 6 pixel stroke location centered. Lock the transparency of the layer and guassian blur 8 pixels. Set layer to Multiply. Inverse selection and Delete.
Copy the Layer if you wish darker edges.
The Shadow and Refraction you probably already know about...