Gems

Gems are valuable crafting materials found underground. There are currently 7 gem types. Gems can also be placed on any side of a block after being mined. They are found in any underground layer, except for The Underworld.

With the exception of Amber (which requires an Extractinator instead), gems are found in the following forms, all of which drop the respective gem items when mined:
 * Embedded within Stone Blocks.
 * In placed form on blocks underground, including sometimes in Underground Cabins, or rarely in the Dungeon.
 * As gem stashes, which are breakable background objects (similar to Coin Stashes), each resembling a rock with gems protruding.

Gems can also be found in higher concentrations in rare gemstone caves, which can contain multiple gem types lining and embedded within their Stone Blocks.

Types
In descending order of rarity and value (rarest at the top):

Gemstone cave


A gemstone cave is a rare, irregularly shaped room often found in the cavern layer. It contains a high concentration of placed gems on multiple stone surfaces, as well as a few gems embedded in stone. Most gemstone caves contain one or two types of gemstone, but can rarely contain three or more types. The type of gem found in such caves is easily identifiable by the Gem Wall the cave utilizes, but this wall cannot be collected to obtain any items.