Its just anodising, don't worry about it.
On Ali theres a thin (at the start) layer of clear aluminium oxide.
In the metal platers they form a thicker oxide layer on the surface of the ali & at the same time they have it dipped in a dye vat.
As the oxide builds up it traps the dye iside the crystal matrix & thats what the colour is. Thin dye in clear oxide.
When they resmelt the Ali, the oxide comes off, floats up to the top with the now destroyed dye compound.
They might add cryolite or flouride or something to resmelt the oxide into ali or something like that.
Its just like paint but seethru.
Ali oxide is hard as diamond almost, thats why they do it too, makes the Ali more wear resistant.
Bookmarks