diff --git a/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java b/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java
index ffabd7d..3f63f26 100644
--- a/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java
+++ b/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java
@@ -139,7 +139,19 @@ public class GameLogic {
                             requireLineOfSight(state, data.originField, data.targetField);
                         }
                         case RealityStone -> {
-                            // no check done
+                            boolean rock = false;
+                            boolean empty = true;
+                            for(Entity entity: state.entities.findByPosition(data.targetField)) {
+                                if(entity.id.type == EntityType.Rocks) {
+                                    rock = true;
+                                    break;
+                                }else {
+                                    empty = false;
+                                }
+                            }
+                            if(!empty && !rock) {
+                                throw new InvalidRequestException("Using reality stone on non-free field without a rock");
+                            }
                         }
                         case PowerStone -> {
                             Character target = getCharacter(state, data.targetField, data.targetEntity);