Soul Crystals are used to put Special Abilities on C-grade and higher weapons. They can range from level 0 to level 13. You level them up by "using" them on certain mobs.
That happens alot. They are not actually drops in the sinse that mobs dropped them. What happens is people take several crystals with them when they go to lvl crystals. You can only have 1 in your inventory while you lvl a crystal. So the hide them or just drop them on the ground untel they are ready to lvl it. So what you found is crystals someone just left laying there. They are worth nothing if they are not lvl'd so people leave them laying around alot.
huh..well..sucks to be those people i guess :p
but still the question remains...how do i lvl a crystal and what mobs do it.(i assume one uses it on a mob or criter or something)
The quest "Enhance your Weapon" tells ya all ya need. U can get it in Giran, Oren and Aden. When u accept the quest, ull get a Soul Crystal of ur choice: Red, green or blue. Throw it on the ground and talk to the guy again to get another crystal of ur choice. Do that untill u think u have enough crystals. Look in ur questlist to see on what mobs u can lvl the crytsal. To lvl a crystal, simply use it before the mobs dies (i usually do this around 1/2-1/3 hp left). Make sure, u have last hit on the mob. Then the crystal might lvl a stage or not, or even brake. U can just have 1 crystal at once in ur inventory to lvl, so drop ur other crystals somewhere on the ground and when the crystal u try to lvl brakes, pick up another one and try again. Note: Not all stages can be done on all mobs. lvl 11/12/13 need special bosses (lilith/Anakim/Zaken/Antharas...), 1-10 can be done on normal mobs (but not all stages sometimes). Forrest of Mirrors is good for 1-5, but u wont get higher there. I usually do Doom Knights, on em u can go up to stage 10 (some ppl do 1-5 on lizards, then 6-10 on knights, i go 1-10 on the knights)
It sounds like you've had bad luck. I usually start with 10 crystals of one color. Stage them all to lvl 1, then all to lvl 2, etc... I start leveling them on Harit Lizrmen and move to Doom Servants after all the remaining crystals hit lvl 5. After all the crystals hit stage 8 then I move to Doom Troopers/Warriors and then to Doom Knights. Starting with 10 crystals I usually get about 3-4 Stage 8s (if I stop at Stg8) or 1-2 Stage 10s.
When It comes to soul crystals I have been very lucky. I have been able to get 4 out of 5 crystals to lvl 7 or higher. After lvl 69 this is a great way to make extra aden you can do 3 quests at the same time. Enhance your weapon, remnance of fallen soldiers and the inferium ore quest all at the same time you lvl crystals. I lvl them to lvl 8 on doom servants they are easier to kill and they have the worms (forgot the name) in same area so you can kill them and get inf ore. All the doom mobs near Devistated castle you can lvl crystals on and get the remnants of fallen soldiers quest items from at the same time.
Just a little side note: Since C4 this area has been totaly taken over buy farmers. I was there last night and counted 15 9 man parties in that area. Buy looking at the names and watching thier movements I could tell they were not normal players either. So if you go up that way be prepaired its full hard to get to some mobs and very very very laggy.