Initially you must turn in seven of each color crystal (red, blue, yellow and green) at the end of the cave right by the camp/fly point in Un'Goro. You will be given a book which will allow you to receive items from the spires. You will need 10 each of 2 colors to collect a Crystal.

Travel to each Pylon to receive your powerful crystal.

Northern Crystal Pylon:

Crystal Charge: 10 Red + 10 Yellow: "Inflicts 383 to 517 fire damage to targets in a 3 yard radius"
Crystal Restore: 10 Yellow + 10 Green: "Heals the target of 670 damage over 15 seconds"

Western Crystal Pylon:

Crystal Ward: 10 Red + 10 Green: "Increases the targets armor by 200 for 30 min"
Crystal Yield: 10 Blue + 10 Red: "Decreases an enemy target's Armor by 200 for 2 min"

Eastern Crystal Pylon:

Crystal Force: 10 Blue + 10 Green: "Increases the targets spirit by 30 for 30 minutes"
Crystal Spire: 10 Blue + 10 Yellow: "A crystal shield surrounds the friendly target. doing 12 damage to anyone who hits him/her. Lasts 10 min."

Northern is at 57,12
Western is at 23,59
Eastern is 78.51

POOR RICHARD'S ALMANACK: The Un'Goro Pylons
By Richard Saunders, Philomath (Silver Hand)

If you're of a level to go to Un'Goro Crater, the first thing you will probably do is die. It's a dangerous place, and the first time I was there I fell in from Tanaris, not a good way to live through an initial encounter. So, when you exit the graveyard, you will have found the Eastern Pylon and will have wondered about it, if you are the sort with wonder in their hearts, and not just playing this game to get to max level as fast as possible so you can PvP with all the other ten-year-olds. But I digress.

A series of quests, initiated by J.D. Collie in Marshal's Refuge (she is at 41, 2 inside the crystal caves that are behind Dadanga) lead to your rewards. You can however begin harvesting the coloured power crystals much sooner by level 44 I had a fair stock of them, as they often pop up in untenanted areas. You will probably meet her when going through the Linken series of quests. The first crystal-related quest requires you to give her seven of each colour of the power crystals. Then you need to find the three pylons, yes, even if you've found them before. She will then give you a User's Manual to the pylons, which you may discard as your humble & obedient Servant, Poor Richard, has expanded upon it herein.

Pylons give up 6 of each item when you activate them. Sale price is 10s for each one. (So I guess the power crustals are worth 3s each-- not bad for dodging dinosaurs!) The effect crystals will be soulbound, but not the coloured power crystals

The crystal effects can be grouped roughly as defensive and offensive. Each pylon will give you one from each category. With the exception of Spire, which is a sort of Thorns, the offensive ones are instants and the defensives last a reasonable duration. In the offense group are Charge (fire damage, North pylon) Spire (damage shield, East pylon) and Yield (lower opponent AC, West pylon). More defensive are Force (Spirit bonus, East pylon) Ward (Armor increase, West pylon) and Restore (healing aura, North pylon). One VERY nice thing about Restore is that it doesn't get interrupted while it's working, so you can cast it on yourself in the middle of a fight and it won't get bumped, unlike bandaging and eating. It's saved my hash in close fights more than once and is, I think, my favorite, though I use up an awful lot of the decent flash-bang Charges.

Undisputably the hardest pylon to get to is the Western one,guarded as it is by not only higher level opponents (level 53-55) of all stripes but also the elite stegosauri. Stick to the wall and run when the coast is clear, or use your stealth. The North poylon, though it has a few Pterrordaxes flying about, isn't too hard to access and the Eastern one is safe as houses. You may run into a few level 48 Ravasaurs around it but after you die, talk to the Spirit Healer and get the 25% gear damage res, you can wander to it and fill up on ceystals while waiting for resurrection sickness to go away. And of course there are always the Devilsaurs wherever you go. (How exactly does a twenty story tall prehistoric monster sneak up on you? Created by the Martians to destroy the human race, no doubt. The FBI is helpless.) Synopsis: Fill up on Ward and Yield whil you're in the West it may be a while before you get back to it.

The crystals themselves can be found scattered liberally throughout the Crater. I can see no rhyme nor reason to their layout, and they regenerate quickly. A rule of thumb: If it looks dangerous to get to the area, don't. Another one will be in a safer area. Oh, yes, they also stack to more than 20, so happy collecting!

East pylon 77, 49
CRYSTAL FORCE: Increase Spirit by 30 for 30 minutes. Requires 10 blue, 10 green.
CRYSTAL SPIRE: Damage shield, 12 damage to anyone who hits the user. Lasts 10 minutes. Requires 10 blue, 10 yellow.

West pylon 23, 59
CRYSTAL WARD: Increase Armor by 200 for 30 minutes. Requires 10 red, 10 green
CRYSTALYIELD: Lower opponent's armor by 200 for 2 minutes. Requires 10 red, 10 blue.

North pylon 56, 12
CRYSTAL CHARGE. Does 383-517 fire damage in a 3-yard radius. Requires 10 yellow, 10 red.
CRYSTAL RESTORE: Heal one target for 670 points over 15 seconds. Requires 10 yellow, 10 green.

She is inside a cave: 41,2

This quest opens up 3 more quests which require additional pylons. (lol)