Do people trade Perfect Topaz?

Certain gems are more desired in bulk because they're used for crafting purposes.

Ruby for blood,

Amethyst for caster,

Sapphire for hitpower and

Emerald for safety recipes. Though not all of them are equally as popular/valuable.

There actually is no crafting bulk need for

Topaz so the only reason to get those specifically is for other cube recipes (e.g. socket to body armor). As those are typically only done as a one off however and not in bulk, noone really specifically looks for

Topaz in bulk.

They do get traded as part of "random p gems in bulk" though for the recipes that work with any gem and don't need a specific one (e.g. magic item reroll).