Gems, also known as gemstones or jewels, are items in Breath of the Wild . There are many types of Gems like Ruby, Diamonds, Amber, Opals, Sapphire, and Topaz. They can be found in different ways like opening chests, dropped by a Stone Talus, and a Stone Pebblit, by breaking Ore Deposits, By breaking Rare Ore Deposits. and dropped by defeating Silver Monsters, and Golden Monsters. They can also be found at Tarrey Town after Pelison moves in and opens up Ore and More.
Gems are used for many things like upgrading armor, craft new gear, or be sold at a super high price to shops and merchants like Beetle. Some Gems can be used to purchase and craft accessories at the Starlight Memories in Gerudo Town after you complete a small side quest. There is also a way to sell gems for higher prices then normal stores. After completing the Side quest The Jewel Trade at Goron City, a Gerudo named Ramella will offer to buy ten pieces of a randomly chosen gem for higher prices.