How to make niessing aura ring?

Hi there.

Niessing aura ring are rings that have a gradient from white gold to
red gold.

I would like to be able to create it and also do it in momotones.
i.e. one color in shades gradients.

The alloys with every hue between yellow and rose gold could be made,
but not between white gold and red gold. so i was told…

The shade I’m looking for is a slightly greyish white gold with a
tint of red is just so strong that the acts gray soft, but really
just a hint reddish. According to what I’ve read so far would have
but for example an alloy 750 gold, 150 palladium, 50 silver, 50
copper has a greyish tone to me reddish Note arise?

Are there manufacturing difficulties (too brittle or so) or why does
no one makes it? Thank you in advance -