Excalibur

"'The legendary blade Excalibur stores the value of ores that are sacrificed to it and stacks it onto all new ores for a short time.'"

Overview
Excalibur is an Exotic tier furnace that was exclusive to May 2016 and was introduced in the Outdoors Update. Unlike every other furnace in Miner's Haven, this does not multiply ore value by a specific number. Instead, Excalibur has a unique effect where it stacks ore value from ore previously processed by the furnace. Its effect is quite complicated and it actually isn't useful without the unique ability of adding one ore's value to another. However, this is considered to be one of the best furnaces in the game, as it can make ores of low value become profitable if used correctly. For example, if this furnace is placed with Remote Droppers/Spitfire Iron Mines nearby ores will rapidly increase your profit if a valuable ore is processed.

It was added in early May 2016. It was removed from boxes on June 16th, 2016.

Trivia

 * During the few months, The Masked Man sold this item, it was incorrectly displayed as a Contraband tier.
 * This is one of eight furnaces to have its own unique sound, along with the Thingamajig, Dark Magic, The Fracture, Sage Redeemer, The Sunken Past, Pirate's Loot Collector, and Birthday Cake.
 * Players who also have obtained a Wubium Mine can use it instead of Spitfire Iron Mines because of the mine's insane ore drop rate.
 * If a massive amount of ores is being put into this furnace, sometimes a player's UI will disappear.
 * Before the Blood Magic and Northern Lights were added, Excalibur was considered to be the best furnace in the game.
 * This is the first of two furnaces that holds ores and adds the value of ores onto one ore, the second being the Equinox.
 * Besides the Basic Furnace, this is the only item in Miner's Haven that doesn't have a value it will multiply ores by when processed. Instead, it adds value to ores.