Giant Sword

Sprite
Damage 21
Crit 12%
Hit +20%
Val. 4,000 G

Equipped By

Found In Gurgu Volcano B2
The Giant Sword is a bit less powerful than the Silver Sword, but it does add 5 Hit Rate and has a better crit rate. It is unlikely that the difference in Hit Rate will grant any of your characters an extra attack when you get the sword, but it is still worth noting, and may be useful for RedMAGES just for the increased accuracy.
Compare Giant Sword to other Weapons
Treasures: Containing Giant Sword – 1 shown
Map
The specifics of where this treasure can be found
Notes
Gurgu Volcano B2 In the chest at the west end of the northeastern halls (guarded)
Dragon Sword Sun Sword

Related

Treasure in Gurgu Volcano

The ORB of Fire
Page 3
Gather loot in the Treasure room of Gurgu Volcano B2 before proceeding further.

Claymore

Sword effective against giants.
Damage 21
Crit 12%
Hit +20%
Effective Against Giant
Value 4,000 gil (4,000 gil on Easy)
Found In Mt. Gulg B2

Equipped By

The Claymore is a bit less powerful than the Mythril Sword, but it does add 5 Accuracy. It is unlikely that this difference will grant any of your characters an extra attack when you get the sword, but it is still worth noting, and may be useful for Red Mages just for the increased hit chance. You will be fighting a lot of Giants in the Area anyway, so it's a nice sword to have.

Claymore

Sprite
Attack +1
Type Greatsword
No. 20 Game FFXI
Dropped By Crazy Horse
Swinging around this huge sword is a very effective means of anger management.