This gets set to one if the calling Object is a soulgem and it has been used in either recharging or item making. Must be reset manually for multiple use (set OnPCSoulGemUse to 0 ).
Example: this is how Azura's star becomes an inexhaustible soulgem:
begin AzurasStarScript
;this is for Azura's Star. A never ending soulgem item. Mucho good. Kids love it.