Crystal Hollows

The  is a randomly-generated Mining area. It is the primary source of Gemstones.

Mechanics
The Crystal Hollows is a mining area from to, enclosing an area of 621 x 157 x 621. Bedrock walls enclose the mineable area. This area is partially randomly generated; only the Structures within the cave are randomly generated, with the exception of Crystal Nucleus. The cave tunnels are not randomly generated and are the same across all servers.

In order to access the Crystal Hollows, a pass must be purchased from Gwendolyn. The pass costs and grants access for 2 hours. When the pass is about to expire (1 minute before), it can be renewed by clicking the chat message.

Once the pass is purchased, the Hollows can be entered via the Minecart next to Gwendolyn or the Minecart icon in the SkyBlock Menu. Clicking the Minecart in the SkyBlock Menu while in the Hollows returns the player to the Dwarven Mines.

Every 2 hours (6 in-game days), Crystal Hollows servers reset with a cave-in. Just before a cave-in, the following messages are displayed in chat:

After that, the server restarts and all players will get kicked out and sent to Gwendolyn in Dwarven Mines.

Mining
Inside the Crystal Hollows, blocks that are mined do not get replaced by Bedrock, and are instead removed, similar to vanilla Minecraft mining. You can also place blocks in the Crystal Hollows. Ores that require a furnace do not require Smelting Touch to be obtained.

Stone is replaced by Hard Stone within the Hollows, which is harder to break than Stone. Gemstones, Mithril, and vanilla ores spawn within the Hard Stone.

Yields from vanilla ores are increased within the Crystal Hollows.

Treasure
Upon mining blocks, there is a small chance to spawn a treasure chest, containing various rewards. The player must aim at the critical particles on the face of the chests 5 times in order to open the chest. Treasure chests can also spawn in set locations within structures; these chests can be opened directly.

Treasure chests will only contain the loot found within the area. For example, Magma Fields chests might contain, or.

The possible loot is listed below. Multiple (typically 4-10) stacks of loot generate in 1 chest.

Structures
There are 5 Main Structures each generated in the 5 main locations within the cave: Each of the 5 main structures houses their respective Crystal. A special task must be completed to obtain the Crystal.
 * The Jungle Temple generated in the Jungle
 * The Mines of Divan generated in the Mithril Deposits
 * The Goblin Queen's Den generated in the Goblin Holdout
 * The Lost Precursor City generated in the Precursor Remnants
 * Khazad-dûm generated in the Magma Fields

There are also smaller structures which generate in random locations. Examples include: A full list of Structures can be found at Crystal Hollows/Special Locations.
 * A structure which resembles the Deep Caverns, including the lift and the layered structure of the original Deep Caverns island
 * A dragon skull from the Spider's Den
 * A replica of the Dark Auction
 * A miniature version of The Forge including a working forge NPC
 * A copy of the pre-Hub overhaul Tavern

Certain structures contain loot chests. Loot chests always generate in the same positions within the structures, similar to Dungeon Secrets.

Trivia

 * It is the only place, , , and can be harvested.
 * Any blocks mined in the Crystal Hollows will give their corresponding skill experience, even if it's placed by a player.