Lightning

Lightning, also translated as Thunder, is a material type available in Kingdom Hearts, Kingdom Hearts II, and Kingdom Hearts 358/2 Days. Lightning materials contain the essence of thunder, and are colored yellow.

Design
Lightning materials are represented by yellow-orange jewels with what seem to be bolts of electricity trapped in them. They have an Elemental material structure.

"Lightning" is an atmospheric electrical discharge. The sound of this discharge is referred to as "thunder". This reflects the electricity and "essence of thunder" the material contains.

Kingdom Hearts

 * Thunder Shard: Yellow Opera (8%), White Mushroom (100%), Bambi (40%/60%)
 * Thunder Gem: Aquatank (8%), Screwdiver (4%), White Mushroom (10%/40%), Bambi (30%)

Kingdom Hearts Final Mix introduced the Lightning Stone, dropped only by the Black Ballade.

Kingdom Hearts II

 * Lightning Shard: Bolt Tower (10%), Rapid Thruster (4%)
 * Lightning Stone: Driller Mole (6%), Emerald Blues (10%)
 * Lightning Gem: Armored Knight (12%), Surveillance Robot (8%)
 * Lightning Crystal: Devastator (4%), Strafer (6%)

Kingdom Hearts 358/2 Days

 * Lightning Shard: Poison Plant (Missions 44, 59), Bully Dog (Missions 38, 49, 50), Neoshadow (Mission 38, 44), Jumbo Cannon (Missions 39, 46, 61), Hover Ghost (Missions 36, 45), Lurk Lizard (Mission 47)
 * Lightning Gem: Loudmouth (Mission 68), Solid Armor (Mission 68), Hover Ghost (Missions 52, 62), Dual Blade (Mission 54)
 * Lightning Crystal: Possessor (Mission 83, 89), Hover Ghost (Mission 79), Blitz Spear (Mission 83)

Kingdom Hearts 358/2 Days

 * Lightning Shard: Outside in Mission 36, Vestibule in Mission 39, Vestibule in Mission 46, eastern rock cliff in Mission 53, Outside in Mission 61; open at least 80 chests and talk to Axel on Day 94.
 * Lightning Gem: Outside in Mission 61.
 * Lightning Crystal: Southeast island on South Map in Mission 77, Boneyard 1 in Mission 79, Town Square in 87.

Kingdom Hearts III
Lightning Crystals can be synthesized once 30 different synthesis materials are obtained.

Kingdom Hearts 358/2 Days

 * Lightning Shard: Clear Bonus for Missions 36, 40, 43, 47, 48, 59, and 82; Random Bonus for Missions 36, 39, 40, 41, 46, and 61.
 * Lightning Gem: Clear Bonus for Missions 67, 82, and 72; Random Bonus for Mission 61.
 * Lightning Crystal: Clear Bonus for Missions 73, 74, and 87; Random Bonus for Missions 79 and 88.

Synthesized items
Lightning materials are used to synthesize the following items:

Kingdom Hearts

 * Elixir (2 Thunder Shards)
 * Guard Earring (1 Thunder Shard)
 * Mega-Potion (1 Thunder Gem)
 * Magic Armlet (3 Thunder Shards)
 * Mega-Ether (3 Thunder Gems)
 * Rune Armlet (2 Thunder Gems)
 * Three Stars (3 Thunder Shards)
 * Ribbon (5 Thunder Gems)
 * Ultima Weapon (5 Thunder Gems)

Kingdom Hearts Final Mix

 * Moogle Badge (1 Lightning Stone)
 * Gaia Bangle (1 Lightning Stone)

Kingdom Hearts II

 * Acrisius (1 Lightning Stone)
 * Acrisius+ (1 Lightning Stone)
 * Thundaga Trinket (1 Lightning Shard, 1 Lightning Stone)
 * Thundagun Trinket (1 Lightning Shard, 1 Lightning Stone)
 * Mage Earring (1 Lightning Gem)
 * Slayer Earring (1 Lightning Gem)
 * Drive Recovery (1 Lightning Shard)
 * High Drive Recovery (1 Lightning Shard)
 * Defense Boost (3 Lightning Crystals)
 * Power Boost (3 Lightning Crystals)

Kingdom Hearts 358/2 Days

 * Thunder (2 Lightning Shards)
 * Thundara (2 Lightning Gems)
 * Thundaga (2 Lightning Crystals)
 * Thunder Charm (2 Lightning Gems)
 * Thunder Block Ⓛ (3 Lightning Gems)
 * Stolen Thunder (2 Lightning Crystals, 5 Lightning Shards)

Kingdom Hearts III

 * Ether (2 Lightning Shard)
 * Hi-Ether (3 Lightning Stone)
 * Mega-Ether (3 Lightning Stone)
 * Refocuser (3 Lightning Shard)
 * Astrolabe+ (2 Lightning Gem)
 * Thunder Trinket (2 Lightning Stone, 5 Lightning Shard)
 * Thundara Trinket (2 Lightning Stone, 5 Lightning Shard)

Notes and References
Grondant Donner