Add missing values for artwork_type (#1443)

data/fields/artwork_type.json

@@ -12,7 +12,9 @@
             "bust": "Bust",
             "painting": "Painting",
             "mosaic": "Mosaic",
-            "relief": "Relief"
+            "relief": "Relief",
+            "stone": "Artistically Worked Stone",
+            "tilework": "Tile Work"
         }
     }
 }