This large crystal fragment barely has any garnet peeking out. I chose
this piece because I thought I saw some silk on the surface. A penny is
provided for scale. The preying mantis volunteered his modeling services.
The use of oxalic acid is a well known method for removing iron oxide staining from quartz and I've heard it recommended for star garnet crystals too. Commonly known as "wood bleach", most hardware stores carry it in stock. The downside to oxalic acid is that it is corrosive and toxic. I've been avoiding cleaning my crystals with this method since I share my workshop with a very inquisitive Siamese Cat. Just like a small child- I know he'll find a way into this potential toxic garnet stew.
Recently, I heard of a much easier suggestion- a brass bristle brush. Steel might work too. I had neither. However, I am restoring a rusted-out cabbing machine and do have a rust/paint stripping abrasive wheel (manufactured by 3M) that fits into a hand power drill. Here are the results:
The same crystal face. Rust is nearly all gone. It worked!
A very silky portion of the crystal. This one is a cutter.
This is a great method for a peek into your garnet rough- especially if you don't have a cabbing machine setup. I did test for asterism with the "oil test" and discoverd that this crystal will yield some brightly starred gems. Has anyone tried the brass or steel brush method?