Block of Copper

Copper blocks are decorative blocks that oxidize over time, gaining a viridian appearance. They can be crafted into waxed versions that do not oxidize. They can also be crafted back into nine Copper Ingots unless they have started to oxidize, have been waxed, and/or crafted into the Cut variant.

Breaking
Copper blocks can be mined only with a stone pickaxe or better. If a copper block is mined without the use of a pickaxe, it drops nothing.

Usage
Copper blocks are used for storing copper ingots. Weathered variants, waxed variants, and cut variants have no use except for decoration.

They have four stages of weathering (including the initial unweathered state), and advance to the next stage of weathering every 50–82 in-game days (1,200,000–1,967,999 game ticks, 1000–1640 minutes, or 16 h 40 min – 27 h 20 min). This requires the block to be in a loaded chunk, but isn't reliant on random ticks, and as such works in spawn chunks and other permanently loaded chunks even without a player nearby.

Trivia

 * In real life, copper typically tarnishes to a darker brown color in air due to the buildup of copper oxides and sulfides on the surface. Green oxidation is generally due to basic copper carbonate and requires carbon dioxide to be present in the atmosphere.
 * Weathered Copper Block is misspelled as “Weathered Copper BlocK” in snapshot 20w45a.