diff --git a/src/net/torvald/terrarum/modulebasegame/gameitems/OreItemBase.kt b/src/net/torvald/terrarum/modulebasegame/gameitems/OreItemBase.kt
index 06dd152ea..88da3330b 100644
--- a/src/net/torvald/terrarum/modulebasegame/gameitems/OreItemBase.kt
+++ b/src/net/torvald/terrarum/modulebasegame/gameitems/OreItemBase.kt
@@ -44,16 +44,19 @@ class OreStick(originalID: ItemID) : OreItemBase(originalID) {
 }
 class OreCopper(originalID: ItemID) : OreItemBase(originalID) {
     override var originalName = "ITEM_ORE_MALACHITE"
+    override val materialId = "ROCK"
     override val itemImage: TextureRegion
         get() = CommonResourcePool.getAsItemSheet("basegame.items").get(2,6)
 }
 class OreIron(originalID: ItemID) : OreItemBase(originalID) {
     override var originalName = "ITEM_ORE_HAEMATITE"
+    override val materialId = "ROCK"
     override val itemImage: TextureRegion
         get() = CommonResourcePool.getAsItemSheet("basegame.items").get(3,6)
 }
 class OreCoal(originalID: ItemID) : OreItemBase(originalID) {
     override var originalName = "ITEM_ORE_COAL"
+    override val materialId = "ROCK"
     override val itemImage: TextureRegion
         get() = CommonResourcePool.getAsItemSheet("basegame.items").get(4,6)
 }
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