Pristine Adegan Crystlas are used in the making of Magenta Color Crystals.   They are refined from the Rough Magenta Crystal Shards found on Alderaan. 

You do not need to have Archeology to harvest these crystals.

There are three locations on Alderaan where the rough crystals spawn.  In each location there are two or three spots, but only one will spawn at at time.

This is a quick route I've discovered after doing this many times.   This is long and complicated, I'll make a video soon.

Start at Wardpost Landa.

The building you want is here:

Head up that path to the left:

And climb the rocks.

And here you are.  There are four possible spawn points.  If you have to get to the upper right one, it helps to jump the rocks on a speeder.

The quickest way to the next location is to head north to the river.

Jump the rocks here and head up the path.

Until you get to this droid.  Head up the side of the hill.

Go through the gap at the top and turn right.

If there's not a crystal here, go back towards the gap and look out to the right.  I usually can't see if there's a crystal in the second location from there, I have to get closer.  

You can get there by hopping along the tops of the rocks, but it's tricky.  It's easier to go back to the path and continue on around the hill to where the tents are.

For Imperials, it's faster to go to Location #2 first.  Start at Outpost Bolym, head south along the road to the Organa Medical Camps.)  After harvesting here, reverse the route through the river shown above and head to Location #1.   Then QT back to Outpost Bolym and head north into Kaamos Territory.

 If you thought this was fun, wait until you get to location #3...  Head north to Kaamos Territory.

There's not a path here, just a clearing.

You need to be out on the rocks to be able to see down.

If you're lucky, there will be one here.

If you aren't lucky, there might be one here.

In either case, you need to slide down to this point.  Don't jump, just walk forward.

If you need to go down to the lower one, heal up first, then walk carefully along the rocks.

Then step off to slide down.  Don't jump!  Be sure you're healed up first, as you see I went from 100% to 10%.

You are now done with Alderaan.  You will have Rough Magenta Crystal Shards in your inventory.  (They don't stack)

Time to visit the refinery!

Head to Tython (Korriban for Imperials).

The Ancient Crystal tuning Device is located in The Forge Remnants, so taxi to the Forward Camp and head up the stairs towards the Waterfall Cave.

You may recognize this as a datacron location.  Go past the fleshraiders and make a left, and follow the path around the rocks.

You want to go down under these stone platforms.

And here it is!  If you don't have the Rough Magenta Crystal Shards in your inventory, you will get this message...

The one of Korriban is easier to find.  Taxi to Wilds Laboratory.  Head north and then make a left turn.

The tuning device is located at the end of that path, off to the left.

The refined crystals will appear in your inventory.