What dose the colour purple mean?

I have picked up a peace of gear called aetherial cotton cowl it has much better stats than normal gear and I found it in a chest on a leve quest. But my question is what dose the colour behind the item mean? I also have a weapon with the same colour as well.

Its involved in Relic gear other than that im not sure.

Thats just rarity. The chests will have <type> Pieces x4, <type> Pieces x4 and a <type>Potion, a green Armor, a Pink Armor, or a Pink Weapon (I havent seen green weapons in them).