Topaz

Topazes are yellow socketable gems in both Diablo II and Diablo III.

Diablo II
Like all the other Gems, Topazes grant bonuses that are related to their color. The yellow in Topaz signifies the Elemental power of Lightning. In Weapons and Shields, it adds bonuses related to Lightning, while in Armor and Helms, it adds an increase in Magic Find, a trait also signified by the golden glow of yellow, indicating Prosperity.

Development
Prior to 2.4.2, socketing a Topaz into Helms would increase the Magic Find instead of reducing resource costs, up to 41% for Flawless Royal.

Prior to patch 2.3, Topaz gems in Diablo III had many more tiers, but were condensed for easier crafting.