Mining

• When a character mines rocks for ore, there is a small chance that the character will mine an uncut gem instead of ore. Mining ordinary rocks can produce sapphires, emeralds, rubies and diamonds. Wearing an Amulet of Glory or a Ring of Wealth while mining increases the chance of mining a gem. In addition, after completing the Shilo Village quest, members are able to mine gem rocks, which yield any type of gem but Dragonstone.
  
  

Grand Exchange

• Some players are not interested in improving their crafting skill. These players often sell any uncut gems that they find on the Grand Exchange, which is a location within the game for players to buy and sell items. Because they are uncommon and prized for their high experience point value, uncut gems are often very expensive to purchase on the Grand Exchange.
  
  

Monsters

• Many monsters "drop" gems when they are killed by characters. Gem drops are not very common, and not all monsters drop gems. If a player wants to train for combat and find uncut gems, it is important to determine if a particular monster drops gems before trying to acquire them this way. You can check online sources or ask players in the game if a monster drops gems.
  
  

Gem Stalls

• There are several gem shops within "RuneScape." These shops are designed for players to sell their gems directly to NPC characters in the game, and other players can then buy the gems from the shop. However, because uncut gems sell for much more on the Grand Exchange than they do in a gem shop, finding gems in gem stalls is very rare. Gem stall stocks are dependent upon players selling gems.