Adamantine Robe of the Mage (3.5e Equipment)
From D&D Wiki
Adamantine Robe of the Mage
This plain-looking robe is made of woven adamantine threads, which make it far more durable than it would appear. It is often woven in with white fabric, giving it a grey appearance.
This robe gives a +4 armor bonus, as well as the DR 1/- typical of light adamantine armors, there is no max sexy due to the robe being clothes. It has no check penalty or spell failure chance, and weighs 10 pounds, twice the weight of a normal robe. It costs 3,000 gold pieces, and is always of masterwork quality (though rarely looks it). It can be enchanted as if it were light armor OR a robe, but not both. It has hardness 11 and 22 hit points. With respect to class features, it is treated as either a robe (unarmored) or light armor, whichever would be most beneficial for that specific class feature.
Due to its unique composition (fabric and adamantine), 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.
Despite the name, this type of armor can be crafted in the form of any outfit that covers a significant part of the body, such as a shirt and pair of pants. While uncommon, such variants are favored by changelings and rouges for being fully-functional armor that is suitable for undercover operations. Changelings also love to enchant it as a Vestment of Many Styles (RoE 175), as it makes the outfit even more useful (and does not increase the effective enhancement bonus if the armor is enchanted).
Note on buying/crafting it
Although the robe is nonmagical (at least at first), several spells are used in the crafting process. It requires a DC 30 Craft (armorsmithing) AND DC 30 Craft (Weaving) check, combined with a Magecraft spell and several alchemical baths just to prepare the adamantine, which takes 48 hours over six days. Weaving it into the fabric requires equal care, requiring the same checks and Magecraft spell over three eight-hour days. The materials alone cost half of the market value, assuming the alchemical baths are purchased pre-made. Note that a Magecraft spell must be cast EVERY DAY of crafting, or the robe is ruined and all of the materials are wasted. If the five alchemical baths are instead made by the crafter, they cost 50 gold pieces each for the ingredients (opposed to 100 GP each if commissioned), and each require a separate DC 20 Craft (alchemy) check, and eight hours to create. As such, if a PC wants one, they will most likely either have to find one as loot, or go to a metropolis to find someone with the skill (and commission the alchemical brews).