Once obtained you do not need to have this on your person to enter the lower mines but it DOES need to at least be in bank. If you destroy it, you will not be able to enter (it does not go on keyring)
I looted an arid indicolite shard for the clicky key quest to get past the stone door.
I went to the blue crystals near the door and right-clicked on the shard to get the Flawless Indicolite Shard... and the arid shard remained.
Normally I wouldn't have done anything other than destroy the arid shard except that I had once been bored while killing and had taken an 'extra' shard to the blue crystals and clicked it. I received an emote to the effect that the energy of the shard had gone to boost the lifeforce of Vergalid.
So...
I right-clicked the arid shard again... and I got the same emote about boosting Vergalid's energy.
Well...
I've always been one to test limits, so I continued to right-click the arid shard again and again and again...
The Result...
After 10 right-clicks THE STONE DOOR DISAPPEARED!!!
I did NOT time it exactly, but I believe it remained gone for approximately 10 minutes after which it respawned. I repeated this with the same shard and got the same result. The door disappeared after 10 clickies.
During this time I had a mage toon down in the 'Vergalid Room' and CoH'd myself down. Originally whenever I was near Vergalid I could run all around him and never be aggro. This time (and again I stress it could be coincidence) Vergalid TL'd me to the zone-in with an emote to the effect that he would not deal with me.
SO...
Did I inadvertantly make Vergalid a targetable mob?
Are the Sunderock Springs quests required to actually take on this version of Vergalid?