The most well known crystal sword is probably the Phantom Blade. This particular sword has been in the game pretty much from release. Several other swords with the same graphic were added later, a few of them even had fiery or glowy effects. If you love this graphic, here's a list of the swords available in all their colors. Just in case someone is interested in dual weilding some of these puppies they've been sorted by Main Hand and One Hand since
Main hand weapons can only be used to transmogrify Main hand weapons.*
One of the swords, Sword of the Archmage is Alliance only and changes to a sword with a different graphic if you transfer factions. The Fiery Retributer is no longer available so IF you happen to still have one in your bank, I'd be for transmogrifying it and showing it off! The Elemental Attuned Blade is a random reward from using your cultist outfit to summon elementals in Silithus. The bonus to this sword is that it is Bind on Equip so it can be sold. The original quests have changed and it has not been verified whether or not this sword is still available. Rumor has it, it still is. However it would be much easier to simply do the quest for the Pilfered Ethereum Blade if you haven't already done it.
|Sword of the Archmage *Alliance Only||Main Hand||BoP||Honor Hold Faction|
Has purple fiery effect
|Main Hand||BoP||Keepers of Time Faction|
|Elemental Attuned Blade||Main Hand||BoE||Random reward for killing a summoned mob|
|Ethereum Phase Blade||Main Hand||BoE||Netherstorm Vendor|
Has orange fiery effect
|One Hand||BoP||No Longer In Game|
|Phantom Blade||One Hand||BoE||Blacksmithing|
|Pilfered Ethereum Blade||One Hand||BoP||Quest - Declawing Doomclaw|
|Renetaki's Soul Slicer||One Hand||BoP||Zul'Gurub Boss Drop|
|Vibro Sword||One Hand||BoP||Quest-Cutting Your Teeth|
I must admit that the Vibro Sword is my favorites but then I'm partial to red. I may just have to make a yellow-green set for myself in order to use Renetaki's Soul Slicer as well. There are a couple daggers with the same graphic for any rogues who happen to stealth by, however neither of those daggers are available in game. You might want to take a moment and see if you still have Shard of the Defiler or Wushoolay's Poker in your bank. Happy Hunting!