Foraging items are something you'll be collecting in your Fields of Mistria playthrough to fill out the museum or to hand in for side quests. You'll find most of them outside the mines, but items such as the Crystal Berries are mine-exclusive. In Field of Mistria's major update (November 18, 2024), there's a new side quest you can grab called "Request for Crystal Berries" from Josephine. Crystal Berries can be farmed in any season, but you'll need to reach the Deep Earth level of the mines in order to find them.