Gilded altar

A gilded altar is the highest level altar that can be built in the Chapel of a player-owned house. Like any altar, it can be used to recharge Prayer. When bones or Demonic ashes are used with the altar, the player gains a 250% experience bonus when compared to simply burying the bones. Incense burners contribute to greater bonuses. With one burner lit, a 300% experience bonus is achieved; when both are lit, the bonus is 350%. All incense burners give the same amount of experience. Because of these bonuses, the gilded altar is a popular choice for players wishing to train Prayer.

To build a gilded altar, the player needs 75 Construction, two marble blocks, four gold leaves, two bolts of cloth, a hammer and a saw in your inventory.

The total cost to buy all the materials for the altar is 0 coins.

The total cost to buy the materials for both the altar and Marble burners is 0 coins.

Requirements
The gilded altar can be built as early as level 67 by using a crystal saw (obtained during the Eyes of Glouphrie quest, it allows you to build things 3 additional levels above your own level) and spicy stew (this may possibly boost your level by 5). In order to receive the +5 Construction bonus, three orange spices per stew must be added. Note that although a +6 boost is technically possible, it is extremely rare; such a boost would stack with the crystal saw for a +9 Construction bonus. A +5 bonus is not guaranteed either, and may take several attempts to get. Also note that, while the spicy stew can boost skills, it can also reduce them by the same amount.

Another option is getting 69 Construction and drinking POH tea (from Teak shelves (2)) which, combined with the crystal saw, gives a total boost of +6. The advantage of this method is that the tea boost is certain, as opposed to the stew.

Players often advertise their open altars on the official RuneScape forums in the Community section, on the Events thread. Also, the house-party themed world (currently World 31) can be a good place to look for altars.

Trivia

 * When offering demonic ashes at an altar, the altar's offering animation shows bones instead of ashes.