Added the pound.
The final mephit...
Mineral Mephit
Clim/Terr: Any
Freq: Common
Org: Solitary
Activity: Any
Diet: Nil
Int: Average (8-10)
Treasure: Nil
AL: Neutral
# Appearing: 1-20
AC: 4
Movement: 12, FL 24 (C)
HD: 3+2
THAC0: 17
# Att: 2
Dmg: 1d4/1d4
SA: Glitterdust
SD: See below
MR: Nil
Size: M (5' tall)
Morale: Average (8-10)
XP: 420
These thickly-built mephits look like earth mephits. Their skin and wings glitter with ground mica. The rigid metallic wings have no obvious function in the mephit's magical flight. Like their earthy kin, mineral mephits are clumsy in flight. They have no odor.
These suspicious, greedy, and self-righteous mephits show an attitude common in their native plane of Minerals: They style themselves guards of all treasure, whether or not they own it.
Combat: Mineral mephits attack with two claws (1d4 damage each). Their breath weapon works as glitterdust (no range, 10' radius) three times a day at 3rd level of magic use. They can move through stone walls less than a foot thick as though insubstantial.
Once per hour, mineral mephits can attempt to gate in 1-2 other mephits, either earth or mineral. If two arrive, they are the same type.
Mineral mephits do not breathe and are immune to gas attacks of all kinds. Vacuum and nonmagical impaling weapons do no damage. Passwall or transmute rock to mude destroys them instantly.
Mineral mephits regenerate 1 hp per turn in contact with stone. Gems and jewelry also restore hit points but are consumed in the process, 10 gp of value lost per hp restored.
Source: PSMC1.