{
    "criteria": {
      "requirement": {
        "trigger": "minecraft:placed_block",
        "conditions": {
          "location": [
            {
              "condition": "minecraft:location_check",
              "predicate": {
                "block": {
                  "blocks": [
                    "minecraft:sand",
                    "minecraft:gravel"
                  ]
                }
              }
            }
          ]
        }
      }
    },
    "rewards": {
      "function": "customsus:find_item"
    }
  }
  