From WoWWiki

Bonuses for Stamina can only be obtained through Blue Gems, Green Gems and Purple Gems, as well as a single Meta Gem [Powerful Earthstorm Diamond].

Color	Name	Effect(s)
Blue	[Solid Zircon]	+6 Stamina
	[Solid Azure Moonstone]	+9 Stamina
	[Solid Star of Elune]	+12 Stamina
	[Solid Empyrean Sapphire]	+15 Stamina
	[Charmed Amani Jewel]	+15 Stamina
	[Falling Star]	+18 Stamina
Green	[Jagged Deep Peridot]	+4 Stamina	+3 Crit Rating
	[Barbed Deep Peridot]	+3 Stamina	+4 Crit Rating
	[Jagged Talasite]	+6 Stamina	+4 Crit Rating
	[Jagged Chrysoprase]	+6 Stamina	+5 Crit Rating
	[Jagged Seaspray Emerald]	+7 Stamina	+5 Crit Rating
	[Enduring Deep Peridot]	+4 Stamina	+3 Defense Rating
	[Enduring Talasite]	+6 Stamina	+4 Defense Rating
	[Enduring Chrysoprase]	+6 Stamina	+5 Defense Rating
	[Enduring Seaspray Emerald]	+7 Stamina	+5 Defense Rating
	[Notched Deep Peridot]	+3 Stamina	+4 Spell Crit Rating
	[Polished Chrysoprase]	+6 Stamina	+5 Spell Crit Rating
	[Unstable Peridot]	+6 Stamina	+4 Intellect
	[Timeless Chrysoprase]	+6 Stamina	+5 Intellect
	[Steady Chrysoprase]	+6 Stamina	+5 Resilience Rating
	[Vivid Chrysoprase]	+6 Stamina	+5 Spell Hit Rating
Purple	[Sovereign Shadow Draenite]	+4 Stamina	+3 Strength
	[Sovereign Nightseye]	+6 Stamina	+4 Strength
	[Sovereign Tanzanite]	+6 Stamina	+5 Strength
	[Sovereign Shadowsong Amethyst]	+7 Stamina	+5 Strength
	[Shifting Shadow Draenite]	+4 Stamina	+3 Agility
	[Shifting Nightseye]	+6 Stamina	+4 Agility
	[Shifting Shadowsong Amethyst]	+7 Stamina	+5 Agility
	[Glowing Shadow Draenite]	+4 Stamina	+4 Spell Damage
	[Glowing Nightseye]	+6 Stamina	+5 Spell Damage
	[Glowing Tanzanite]	+6 Stamina	+6 Spell Damage
	[Infused Amethyst]	+6 Stamina	+6 Spell Damage
	[Glowing Shadowsong Amethyst]	+7 Stamina	+6 Spell Damage
	[Balanced Shadow Draenite]	+4 Stamina	+6 Attack Power
	[Unstable Amethyst]	+6 Stamina	+8 Attack Power
	[Balanced Nightseye]	+6 Stamina	+8 Attack Power
	[Brutal Tanzanite]	+6 Stamina	+10 Attack Power
	[Pulsing Amethyst]	+6 Stamina	+10 Attack Power
	[Balanced Shadowsong Amethyst]	+7 Stamina	+10 Attack Power
	[Regal Tanzanite]	+6 Stamina	+5 Dodge Rating
	[Defender's Tanzanite]	+6 Stamina	+5 Parry Rating
	[Blessed Tanzanite]	+6 Stamina	+11 Healing
	[Soothing Amethyst]	+6 Stamina	+11 Healing
Meta	[Powerful Earthstorm Diamond]	+18 Stamina	5% stun resist