Right click on the gold ring and choose Clone Ellipse. Nothing will appear any different in your drawing because the cloned ellipse is directly on top of the original one. Change the line on the top ellipse to a white color and a 1pt line width. Now your drawing should look like the circle on the left shown above.
Select the blend tool in the toolbox. Click on the outer edge of the gold ring, then drag the cursor inside until the cross-hairs intersect with the white line of the second circle, then release the mouse button. Go to the infobar and change the blend settings from 5 steps to 10 steps. This will smooth out the appearance of the blend. Now you should have a 3D ring like the one shown to the right in the image above.
