Mithralweave (3.5e Equipment)
From D&D Wiki
After killing an evil necromancer, Angelika the Elvan Wizard discovered that the plain looking robe he wore was actually an enchanted Adamantine Robe of the Mage. This plain-looking robe is made of woven adamantine threads, which make it far more durable than it appeared. Not being found of Adamantine due to its difficulty of use, she created a lighter version using mithral.
Mithralweave can be used in any fabric based items, but is most commonly used in Robes and Outfits (Like the breeches or a skirt, a shirt (perhaps with a vest or jacket) from an Explorer's Outfit). Due to its unique composition (fabric and mithral blend), it is treated as metal armor for all spell and environment effects that affect metal, and has a +2 circumstance bonus on reflex saves to avoid catching on fire. It is always of masterwork quality; the masterwork cost is included in the price.
Clothing made from mithralweave gives a +2 bonus to armor class. It has no check penalty or spell failure chance, and weighs the same amount as a regular item. Items cost 1,000 gold pieces more, and are always of masterwork quality (though rarely looks it). It can be enchanted as if it were Light Armor OR a Wondrous Items of the same type, but not both. It has hardness 7 and 14 hit points. With respect to class features, it is treated as either clothing (unarmored) or light armor, whichever would be most beneficial for that specific class feature. In order to gain these bonuses the person needs to wear clothing made of mithralweave covering most of their body (like pants and shirt or a robe). However if armor is worn over the mithralweave clothing, it loses its entire armor bonus.
Creating Mithralweave Items
It requires a DC 15 Craft (Armorsmith) to create the mithral thread, or can be purchased. It then requires a DC 15 Craft (Weaving) check to make the mithralweave fabric. The materials alone cost half of the market value. As such, if a PC wants one, they will most likely either have to find one as loot, or go to a small city or larger to find someone with the skill to create it.