Eldritch Monolith also known as an Eldritch Obelisk, are landmarks from the Thaumcraft mod that spawn randomly in all types of terrain.
These dark edifices are a source of endless debate and mystery. Those brave souls who have ventured close tell tales of inhuman whispers, strange symbols and the remains of ancient temples. The surface of the monolith itself seems to reveal an inner world of endless and alien stars. It is said that should one gaze too long madness may result.
Obelisks found in forest, plains, mountain and jungle biomes are surrounded by a small floor made out of various types of stone bricks and up to four pillars made out of circular stone bricks. Obelisks in desert biomes are surrounded by sandstone instead, and have up to four pillars made out of various types of ornamental sandstone. In swamp biomes, the floor and the pillars surrounding the Obelisks are made from mossy cobblestone.
Below the Obelisk is a shaft made out of unbreakable Eldritch Stones which reaches to the very bottom of the map. Those Eldritch Stones themselves are seemingly indestructible and resist even the most sturdy of diamond pickaxes. (but they don't resist diamond Tunnel Bores. Testing done in Recommended build 7.2.6 shows that a sapphire pickaxe and Void Crusher can harvest these blocks, allowing for you to make a spiral tunnel down to the secret chamber.)
Getting access to the Main Chamber
Warning: When you open a monolith, the Taint level in that chunk will rise. It gets worse after you open the four more seals inside the main chamber (aka. four additional chambers). Be prepared to deal with the Taint with mini Silverwood Trees (one block of Silverwood with one block of Silver wood leaf on top) or other methods. A chunk with closed monolith already has higher Taint than normal since the outside pillar generates some Taint constantly.
Directly below an Obelisk is a panel with four slots. Think of this as a lock to the shaft and the treasure room below for which you need four keys to open. The "keys" in this case are Vis Crystals (NOT the crystal ores!), which you need to equip and place with a right click in the right slot.
Every slot accepts only one specific type of crystal. If you place a wrong crystal, it will generate a 3x3 mild explosion, damaging and possibly killing you if you are already injured. You will also lose the crystal you placed.
However, if you have the Goggles of Revealing equipped, you can see four symbols levitating over the stone in the middle. Those symbols indicate which types of crystals you need to place.
The picture on the right (→) shows all symbols that can appear.
There are 6 types of Crystals that could be inserted within the slot: [This list excludes Depleted Crystal (White)]
Vis (Purple), Vaporous (Yellow), Aqueous (Blue), Earthen (Green), Fiery (Red), and Taint (Violet)
Once you have correctly placed all four crystals, the crystals, the slot stones and the middle stone will disappear in a puff of smoke and you will be able to access the shaft.
However, you should take some precautions. As the main room is situated at the bottom of the map right above the bedrock, you will, at the very least, fall over 50 blocks down - this will kill you, even if you are on full health and have a complete set of diamond armor equipped!
One of the easiest ways of getting down is to take about one stack of sand and place it right into the shaft. The blocks will fall down and then stack up. Once this 1x1 sand tower has arrived at the top of the shaft, you stand right on top of it and dig down. You can then proceed to loot the room (don't forget to take the Void Chests with you, too!). To leave, just jump and place the sand below you until you are at the top of the shaft again.
If you have Boots of the Meteor enchanted with feather fall equipped you can survive the fall quite easily - armor will allow you to reduce the level of enchantment on your boots.
Alternatively, you can equip a Sword of the Zephyr and just hop in. Getting out, however, requires both precision to hit the 1x1 opening, and the durability damage that comes with using its special ability.
Another very easy way to get down if you've used a fair amount of Equivalent Exchange is to use the Swiftwolf's Rending Gale as it negates all fall damage and allows you to fly as in creative mode. The Hurricane Boots will also work when equipped, but they are extremely costly to make.
IC2 Rubber Boots are also a good way to get down as they absorb most of the fall damage you would receive. The Quantum Suit is also a good method as it severely lessens fall damage.
Using an Electric Jetpack from IC2 is another way to get down, as you can slow yourself down when you're near the bottom. You can use the Y cords to see how far away bedrock is, and when to put on the brakes. This is also a method to get back up.
Another method is to make a bunch of ladders, and use a bucket of water at the top of the hole. Pick up the water as you jump down, and you'll drop slowly to the bottom. Afterwards, use the ladders to climb back up. This has the added bonus of leaving an easy way to access the chamber at later points in time.
The cheapest way of getting down is to tame a bird from Mo' Creatures, and wear it on your head. This will allow you to slowly fall down the shaft and take no fall damage. You will, however need to find a different way up after using this method, as a five-ounce bird cannot carry a 160-pound human!
Yet another option is to make a few ropes, then drop them down.
The Main Chamber
At the very bottom of a shaft, right above the bedrock, is a small chamber that contains four Void Chests filled with a variety of Eldritch Artifacts and items like Void Ingots and Seeds of Darkness. You will need those items and artifacts to research and create powerful endgame items like Void Bracelets or Void Chests.
Sometimes, if you are lucky, one of the chests will have a Void Interface right on top of it (there is a Void Interface on the right chest in the screenshot at the right). The interface gives the Void Chest it is connected to a functionality similar to Ender Chest. When you right click on the interface, you can switch between the runes and see (and loot!) all chests linked to currently active rune.
Additional Secret Chambers
Upon entering the main chamber, you'll encounter four (4) Keystone Slots which requires Eldritch Keystone: Tlhutlh
- Shard of Strange Metal (<-- Start here, or you can skip this with exceptional artifact)
- Void Ingot (<-- Not a research material, but it unlocks research for Eldritch Mechanism once you discover this)
- Eldritch Mechanism (<-- Use this as a research material with exceptional eldritch artifact for high chance of obtaining a theory of it, or for the sake of convenience)
- Inert Eldritch Keystone (<-- Use this as a research material again)
- Eldritch Keystone: Tlhutlh
Follow this research arrangement first before proceeding to additional chambers!
Each key-slots leads to additional chambers, which generates upon opening it (by inserting the Keystone on an embedded slot).
Upon opening an additional chamber, it generates (0 - 4) chest(s) with random items inside each chest, and (0 - 5?) Vis crystals with random crystal type.
Although it has a low chance of spawning, this is the only chamber that spawns Void Compass.
Warning: The Keystone slot itself has the same block durability as Eldritch Stone, and never drop as a block when destroyed (even with Silk Touch enchantment), therefore breaking makes it inaccessible permanently.
- In Technic 7.2.6 version of Thaumcraft, the Eldritch Monoliths that you find are unbreakable except by using Block Breaker to totally destroy the monolith. They only go down two levels when you find them. The rest of the monolith is only generated after you open them. Then you can break the Eldritch Stone blocks as usual to make a stair down it if you want. Or sand/fly down, your choice.
- The secret chambers inside the monolith are only generated after you open them. Using Creative mode to destroy the entrance to the secret chamber will not generate the chamber so you have just wasted a monolith spawn!
- You can switch the Void Interface while in the chest to get the other items instead of unlocking another Obelisk (only in earlier version of Thaumcraft, in the later versions, the chests are created after you open the monolith, which means that you can only access previously discovered chest).
- An Eldritch Monolith can be moved and duplicated by using 3rd party software such as MCEdit.
- Each Eldritch Monoliths absolutely spawns in the center of a chunk making them easy to be seen even when covered with different blocks in a different pattern. Comparing this with Mystcraft's Obelisk, it spawns in random position, therefore you cannot mistake it with a different one.
- If you haven't researched the Goggles of Revealing, you can still enter blindly, there's a trick where you avoid wasting a lot of crystals (that ends you up no crystals left) just to open it, by simply using a specific type of crystal that has more quantity than other crystals, and use the other crystals that has less quantity as a last resort.