Gem rock

Gem rocks yield gems when mined instead of ore. They give 65 Mining experience per rock, regardless of what gem is mined. 40 mining is required to mine these rocks.

The types of gems that can be mined are:


 * Opal
 * Jade
 * Red topaz
 * Sapphire
 * Emerald
 * Ruby
 * Diamond

The gem received is random - rocks are not bound to specific gems. (Except for the rocks found during The Tale of the Muspah) It is rare to receive more expensive gems such as rubies and diamonds. Gems are mined at a faster rate while wearing a fully charged Amulet of glory.

Respawn time is about a minute, though the rate changes depending on how many players are connected to the server.

A popular technique when mining these rocks is to bring a chisel and cut and fletch the gems into bolt tips thus reducing the need to bank.

Another popular technique is to drop the less valuable gems such as jades and opals to maximise the amount of money made.

Based on a sample of 1084 consecutively mined gems at Shilo Village (with Rune pickaxe & Amulet of glory), the chance of mining each type of gem is as follows:





Locations

 * Shilo Village after completing the Shilo Village quest.
 * Shilo Village Underground Gem Mine after completing hard tasks of Karamja Diary.
 * Lunar Mine after completing Lunar Diplomacy.
 * Ice cave, found during The Tale of the Muspah (Only contains sapphires, no xp is gained from these rocks and cannot be mined again).

Tai Bwo Wannai Cleanup Minigame


Gem rocks can be found randomly while hacking jungle in the Tai Bwo Wannai Cleanup minigame. When a player discovers one, a message will appear saying: "The jungle parts to reveal a gem-rich rock". These rocks have gems encrusted on the surface, which disappear as the player mines it. The rock may be mined three times before disappearing. The colours of these gems are not an indication of which gems the player will actually mine.

Trivia

 * After mining a rock, you get a message, That says 'You just mined an Opal, Diamond, etc. However, with Jade, it says, 'You just mined a piece of Jade'. The reason being is because in Chinese history, Jade was often used to make pottery and therefore, comes from a larger abundance of jade.