Best way to get early crystal items(cyan) and eternal items is through ascending your character and picking treasured perk. You can ascend your character when you reach lvl 99, this can be bought in shop with 5 million gold.
You will also need eternalized affixes to increase eternal item drops, crystalline set affixes to increase crystal item drop and mythical set affix to increase mythstone drop.
Those purple items are mythic items which can be crafted using zircon(4 sockets) and placing specific mythstones(4) to create a certain mythic item.
Here are the mythic skills/affixes check it out!