diff --git a/src/pocketmine/block/Block.php b/src/pocketmine/block/Block.php
index 344519f56..9fc9e0d85 100644
--- a/src/pocketmine/block/Block.php
+++ b/src/pocketmine/block/Block.php
@@ -39,6 +39,7 @@ use pocketmine\metadata\MetadataValue;
 use pocketmine\Player;
 use pocketmine\plugin\Plugin;
 use function array_merge;
+use function get_class;
 use const PHP_INT_MAX;
 
 class Block extends Position implements BlockIds, Metadatable{
@@ -268,6 +269,7 @@ class Block extends Position implements BlockIds, Metadatable{
 	 * @param Item $item
 	 *
 	 * @return float
+	 * @throws \InvalidArgumentException if the item efficiency is not a positive number
 	 */
 	public function getBreakTime(Item $item) : float{
 		$base = $this->getHardness();
@@ -279,7 +281,7 @@ class Block extends Position implements BlockIds, Metadatable{
 
 		$efficiency = $item->getMiningEfficiency($this);
 		if($efficiency <= 0){
-			throw new \RuntimeException("Item efficiency is invalid");
+			throw new \InvalidArgumentException(get_class($item) . " has invalid mining efficiency: expected >= 0, got $efficiency");
 		}
 
 		$base /= $efficiency;