Forager

There are 4 gemstones you'll collect as you play through this game: Ruby, Topaz, Amethyst and Emerald. You'll get them pretty early on mining random rocks. Getting these are completely random but you just need one of each and doesn't take too long with the amount of mining you will be doing in this game. As you upgrade and level up, you'll get a higher chance of finding these as you mine.

There are 4 gems for you to find: Amythest, Emerald, Ruby and Topaz. These are found randomly when digging or mining rocks.

Gems are more common in the snow biome (4% chance per rock) and volcano biome (5% chance per rock), found to the north and south respectively.

You don't actually need the gems in your inventory. If you have the gems in a vault, the achievement will still unlock.