diff --git a/src/output/VTKWriter.hpp b/src/output/VTKWriter.hpp
index e1ce501814c5a71e686b103417c3f118998f4053..d2459353e4bffa282eac8ff27e21c63d93273664 100644
--- a/src/output/VTKWriter.hpp
+++ b/src/output/VTKWriter.hpp
@@ -354,7 +354,7 @@ class VTKWriter
               break;
             }
             case CellType::Diamond: {
-              types[j] = 42;
+              types[j] = 41;
               break;
             }
             default: {