The Parry All Attacks Gem is a special gem which gives the ability to parry any attack including shield bashes and monstrosity claw attacks. It can be only equipped with dual weapons, and can be sold for $500,000. It is very rarely dropped as loot from chests or Titans, and can be rewarded from Rare Gem Wheels. In Infinity Blade III, it is called 'Combat Great Parry All Gem', it is triangular in shape and can be equipped on heavy weapons, light weapons or dual weapons (any weapon with a triangle slot).
The Parry All gem does not have a definite recipe; the gem is created randomly. The easiest way to get it is to buy a Rare Gem Wheel, as the gem doesn't have an actual recipe. If you want to forge one, however, you can try this combination: On Parry get XP ($500,000 value), On Stab get Gold ($500,000 value), and On Magic Titan Break +1 ($125,000 value), or, On Stab get Gold ($500,000 value), On Parry get XP ($4xx,xxx value), and On Magic get XP ($125,000 value), both in their respective orders. (For IB2)