Different Rune Colors?

I've come across this before and was wondering. What is the difference between a Gold Rune of Major Absorbtion and a Purple Rune of Major. The stats are the same, so what's different?
(see Picts)
Thanks

There is no difference other than the cost of the armor. Gold armor costs the most and is the only one that can give you a superior rune along with major runes. Purple armor costs more than blue armor and has the capability of getting major runes and minor runes. Blue armor is simply the least expensive when identified and can only give you minor runes.

There is no difference between those runes. Anytime you apply any rune to your armour (minor, major, or superior) it will be blue. To the best of my knowledge a blue tint indicates an item containing magical or bonus properties.

The gold armour is a monsters dropped armour. It is an unsalvaged rune. When you salvage that major rune it's title text color will be purple. Monster armours are unwearable by players but can be salvaged for crafting materials or runes, or just sold back to the merchant.

If a monster armour is gold (indicating rarity) it will contain a major or superior rune when id'd and then salvaged. If the armour color before salvaging is purple then it will contain a major or minor rune. If it is blue then it will contain only a minor rune. If it is white then it contains no runes at all.