All the "common" gems are equally rare and at equal qualities worth the same/store the same amount of favor. The Black/Star gems are rare versions of their respective "common" counterparts. All the "rare" gems are equally rare and at equal qualities worth the same/store the same amount of favor. Their value and ability to hold favor is double that of the common ones though.
Some unique gems were received from [[easter egg]]s in 2006. Another unique gem which is not found anymore is the [[Glass Crazy Diamond]].
''Note: Gems cannot be stored in anything like a bulk container. Most players keep them in a large chest or in satchels/backpacks.''