Exchange ratio among various gems?

I know

Perfect Amethyst has the highest value among all kinds of gems,

Perfect Ruby and

Perfect Skull also have higher values, but what should exchange ratios among different kinds of

Perfect Gems be.

I am thinking something like:

1

Perfect Amethyst = 3 misc

Perfect Gems (

Perfect Diamond,

Perfect Topaz,

Perfect Emerald and

Perfect Sapphire)
1

Perfect Ruby = 2 misc

Perfect Gems
1

Perfect Skull = 2 misc

Perfect Gems

Moving this to main forum so it gets some more attention.

Amethyst 3x I agree
Skulls 1 - 1.5x

Ruby 1 - 1.25x

I feel like everytime I look at pgem sales, the Amethysts are gone, and the seller is trying to get a premium on

Perfect Ruby/

Perfect Skull but no one ever buys them.

Being a renowned expert on the subject, I'd say

Perfect Amethyst are worth as much as any other perfect gem... So I'm ready to offer 2

Perfect Gems for every perfect amethysts you guys have!

It's widely agreed that P-ameths are the most valuable gems of them all.
For me personally though, I place topazes in the same value category as rubies. Topazes are great for socketing into head or body armor to increase MF (only 1% behind socketing with

Ist rune), plus topazs are involved with the socket recipe to turn a White armor into a 1 to max socket runeword base, which I like to use alot. So I personally value gems at:
1. Amethysts
2. Rubies & Topazs
3. Diamonds, Sapphires
4. Emeralds
5. Skulls

For the purposes of trading though, it really depends on the buyer/seller when it comes to non-Amethysts, YMMV.