Topaz

Topaz is an ore in BOTH Vanilla Azure Mines and Azure Mines Modded. In AMM, it is used for the exact same purpose as in vanilla (upgrading the marketplace). In AMM it also has a pickaxe for it. It is found at the depths of 20-2000m in caves only. It is a slate textured orange-yellow block that glows amber.

Tips:

If you can, try to find large caves because they often contain more Topaz.

Trivia:

In real life, Topaz has an assortment of colours.