Magical item

A magical object is an item which when polymorphed, has a tendency to become another magical object of the same type.

Magical armour
Only the following items of armour are considered magical:

Cloaks
Bold textprotection]]
 * alchemy smock
 * cloak of displacement
 * cloak of invisibility
 * cloak of magic resistance
 * [[cloak of http://images.wikia.com/common/skins-200802.4/common/images/button_bold.png
 * elven cloak
 * robe

Gloves

 * gauntlets of dexterity
 * gauntlets of fumbling
 * gauntlets of power

Shields

 * shield of reflection

Helmets

 * cornuthaum
 * dunce cap
 * helm of brilliance
 * helm of opposite alignment
 * helm of telepathy

Boots

 * elven boots
 * fumble boots
 * jumping boots
 * kicking boots
 * levitation boots
 * speed boots
 * water walking boots

Suits

 * Each type of dragon scale mail (not dragon scales however)

Magical tools
Only the following tools are considered magical:
 * bag of holding
 * bag of tricks
 * crystal ball
 * drum of earthquake
 * figurine
 * fire horn
 * frost horn
 * horn of plenty
 * magic harp
 * magic lamp
 * magic marker
 * magic flute
 * magic whistle
 * unicorn horn

Magical stones
Only the following stones are considered magical:
 * loadstone
 * luckstone
 * touchstone

Other objects
All potions are magicals except:
 * Potion of acid
 * Potion of booze
 * Potion of fruit juice
 * Potion of oil
 * Potion of sickness
 * Potion of water

Other magical items are: all non-blank scrolls (except scroll of mail), non-blank spellbooks, wands (except wand of nothing), rings (except meat ring), and non-fake amulets are magical. Unique items are also magical, but cannot be polymorphed.

Note that no weapon, food, boulder, or statue is magical.