now with 100% less snowflake

code/game/objects/items/stacks/sheets/mineral.dm

@@ -220,6 +220,7 @@ var/global/list/datum/stack_recipe/abductor_recipes = list ( \
 	origin_tech = "materials=4"
 	sheettype = "tranquillite"
 	materials = list(MAT_TRANQUILLITE=MINERAL_MATERIAL_AMOUNT)
+	wall_allowed = FALSE	//no tranquilite walls in code
 
 /obj/item/stack/sheet/mineral/tranquillite/New(loc, amount=null)
 	..()

code/game/objects/items/stacks/sheets/sheets.dm

@@ -13,6 +13,7 @@
 	var/full_window = null			//moving the var declaration to here so this can be checked cleaner until someone is willing to make them share a base type properly
 	usesound = 'sound/items/Deconstruct.ogg'
 	toolspeed = 1
+	var/wall_allowed = TRUE	//determines if sheet can be used in wall construction or not.
 
 
 // Since the sheetsnatcher was consolidated into weapon/storage/bag we now use

code/game/objects/structures/girders.dm

@@ -201,6 +201,9 @@
 			return
 
 		var/obj/item/stack/sheet/S = W
+		if(!S.wall_allowed)
+			to_chat(user, "<span class='warning'>You don't think that is good material for a wall!</span>")
+			return
 
 		if(istype(S, /obj/item/stack/sheet/wood))
 			if(state == GIRDER_DISPLACED)
@@ -313,9 +316,6 @@
 
 		if(S.sheettype)
 			var/M = S.sheettype
-			if(M == "tranquillite")	//tranquilite walls don't exist in the code (yet)
-				to_chat(user, "<span class='warning'>You don't think that is good material for a wall!</span>")
-				return
 			if(state == GIRDER_DISPLACED)
 				if(S.get_amount() < 2)
 					to_chat(user, "<span class='warning'>You need at least two sheets to create a false wall!</span>")