Repairing chipped agate

Hello!

I'm a newbie here on the forum.  I have an important question, I was working on wire wrapping an agate pendant when I dropped it!  It is a free form shape but the corner of the agate chipped off.  Is there any way I can sand this down?  And if so how do I do it???  The stone is a moss agate, the pendant is about 2" long, the thickness is about an 1/8 of an inch.  I'll try to upload a picture. 

Any help would be fantastic.

Thanks!

Vicki