There is no player-obtainable raw gem named Tanzanite, so there are no craftable designs for them. However, there are a number of cut tanzanite gems that drop from instance bosses in Heroic mode.

Purple, match red or blue sockets.
Name	Effect		Source (Heroic Bosses)
[Blessed Tanzanite]	+6 Spell Power	+6 Stamina	Sethekk Halls
[Brutal Tanzanite]	+10 Attack Power	+6 Stamina	The Botanica
[Defender's Tanzanite]	+5 Parry	+6 Stamina	The Mechanar
[Fluorescent Tanzanite]	+6 Spell Power	+4 Spirit	Blood Furnace
[Glowing Tanzanite]	+6 Spell Power	+6 Stamina	The Black Morass
[Imperial Tanzanite]	+5 Spirit	+5 Spell Power	The Botanica
[Regal Tanzanite]	+5 Dodge	+6 Stamina	Shadow Labyrinth
[Royal Tanzanite]	+6 Spell Power	2 Mana per 5 seconds	The Slave Pens
[Shifting Tanzanite]	+5 Agilty	+6 Stamina	The Steamvault
[Sovereign Tanzanite]	+5 Strength	+6 Stamina	Shattered Halls

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