To create a Crystal Weapon from scratch you need to begin with a standard weapon ( one that you can appply pine resin to otherwise it is unique and will not work )
First you will need the Crystal Ember which is found in Duke's Archive (See vid for the location,credit to Marce1024 for the vid) which you then give to The Giant Blacksmith which is in Anor Londo (which is after Sen's Fortress) this will allow you to access the Crystal weapons.
In order complete the Crystal weapon you will ultimately require 9 Titanite shards , 9 Large Titanite shards , 9 Chunks of Titanite and 1 Titanite Slab
Titanite Chunk - 100% drop rate off the first and third Black Knight in Kiln of the First Flame. These enemies do respawn
Titanite Slab - is a VERY rare drop off Darkwraiths in
New Londo Ruins and also a 100% drop off of the Stray demon in the Undead Asylum (tutorial area) underneath the place you fought the Asylum Demon (first boss about 2 min into the game). The asylum can be revisited via the massive crow who you can see at Firelink Shrine who brought there in the beginning of the game.
Here is a Chart which was created by an unknown so credit to whoever they are.
TRICK-To get the achievement without using your items simply fully upgrade the item in one shot and wait until the achievement pops WITHOUT leaving the upgrade window thus not allowing the game to save the data then simply turn off the game and turn back on.