Crystal detector stands have become expensive and hard to find.  Here's a highly satisfactory design inspired by Elmer Osterhoudt that you can make without needing a machine shop:
 

The heart of this stand is a common Fanestock clip.  These are the old fashioned spring-type wire terminals.  If you can't dig one out of the junk box, Antique Electronic Supply will sell you a life-time supply.  The rod is 1/16" brass from the hobby shop.  The 1/2" wooden bead is a standard craft store item.  The catswisker is a piece of 0.008" steel guitar string soldered to the rod. The end is clipped  at an angle to provide a sharp point.  I glue a small piece of brightly colored wire insulation near the end of my cw's to improve visibility.

The Fanestock clip is mounted with a 3/4" through spacer (unthreaded) and a long #6 machine screw.  Below the panel there is a solder lug, a compression spring, and a  nut.  I use elastic stop nuts to maintain moderate spring tension without coming loose.  Two ordinary nuts jammed against each other will work as well.

This arrangement gives the catswisker three degrees of movement to reach any part of the crystal.  The thin spring-steel wire allows the delicate touch required to get good performance out of galena.

The crystal holder shown was made from lamp parts.  I soldered a 4-40 nut inside the side of the cup to provide good threads for the thumb screw.  A simple U-bracket of tin or hobby brass works as well.