Boulders

Boulders are Salt's solution to mining. They vary in rarity, color and frequency. The big boulders cannot be mined.

Weak Boulder
The most common boulder is an black-colored one. When mined it may contain:
 * Stone Block (always)
 * Flintstone (common)
 * Coal (uncommon)
 * Rough Topaz (rare)
 * Rough Ruby (very rare)
 * Magnetic Stone (very rare)
 * Rough Diamond (extremely rare)

Rich Boulder
It looks like a weak boulder but has a green-colored pattern and is rarer. It can contain the same things as weak boulders, plus:
 * Hardstone Ore (common)
 * Ironite Ore (semi-common)
 * Silver Ore (rare)
 * Rough Topaz (rare)
 * Rough Diamond (rare)

Ironite Boulder
This boulder is often found on Battlemaster settlement islands.
 * Ironite Ore (one or two)
 * Silver Ore (rare)
 * Obsidian Ore (rare)
 * Magnetic Stone (uncommon)
 * Rough Topaz (common)
 * Rough Ruby (rare)
 * Rough Diamond (very rare)

Cobalt Boulder
This is currently the rarest boulder in the game, found only on islands with Pirate Strongholds.
 * Cobalt Ore (one)
 * Flintstone (common)
 * Silver Ore (common)
 * Ironite Ore (rare)
 * Rough Ruby (rare)
 * Rough Diamond (rare)

Moonrock Boulder
These are found only at night on uninhabited islands and have a cyan-colored neon glow during the nighttime which makes these boulders easy to see. Note that these boulders do not glow if the moon is not out.
 * Moonrock Ore Shard (one)

Volatile Boulder
These boulders exist only on desert Islands and usually contain 1 volatile ore per boulder. The player should be really careful when mining these boulders as they will explode when struck by a critical hit. The blast will be pretty harmful to a player without armor.
 * Volatile Ore (one)

Finding special ores and materials
Some ores and materials can rarely be found when mining boulders with special pickaxes:
 * Gold Ore (mining Weak/Rich boulders with the Gold Digger's Pickaxe)
 * Obsidian Ore (mining Weak/Rich/Volatile boulders with the Blacksmith's Pickaxe)
 * Ancient Shard (mining Weak/Rich boulders with the Pick of Crumbled Wardens)