If we talking special order colours how do you price them

When I was selling mine I had many a text or all saying I sold my mint white sapph for £7000or I can buy a mint moonstone for a lot less than what mine was up for and tbh I never replied or wasted my time as to me it's all said in there quote

And I think to my self how many Swartz black sapphs do you see up for sale with my spec and condition and history low miles and low owners