Specifics on soft-box set-up:
Lighting the space behind and around your subject requires a lot of care, patience and finesse.
Controlling the amount of light taken into the camera is another important concept to understand when trying to utilize the style of Back Lighting. 
We discussed controlling the amount of light your camera receives in “Camera Troubles” through “Part 6” and how it is based on the operation of the human eye, nervous system and brain.
Lighting for jewelry is a tricky occupation because of the many shiny surfaces we so enjoy not just of the metal but the gems too. Back Lighting jewelry uses the least direct lighting in my opinion. (I say in my opinion, because like any other profession you will find many an expert who: knows what others do not and used or has seen extremes which others have not. Yes, truly this is experience and opinion wrapped up into one statement.)
There are a couple of ways to back light a subject even in a “light-box”. The first way is to reflect the light off of the back drop. Another way is to light the object through the sheer fabric of the soft box back. I created a kind of soft box, only because I diffused the major lights in my set-up.
So my basic point is; there is no need to buy soft boxes if you are not focusing on staged macro photography. Have fun and improvise with the equipment you have or invest in basic equipment that you can re-use for other projects. Soft boxes are not designed to eliminate all shadows but do a very good job of softening them, especially since setting up proper lighting means more than one light source which the soft box technique so easily facilitates.
Step 1: Soften harsh lighting.
Foe-toss | LIGHT 