diff --git a/GeoModelVisualization/VP1GeometrySystems/src/VP1GeometrySystem.cxx b/GeoModelVisualization/VP1GeometrySystems/src/VP1GeometrySystem.cxx
index 3e97ae23600afe0426ec99427236e4f6ce62a528..b6b1d0f9a233c1852b14e69898016d0bfbcbec8c 100644
--- a/GeoModelVisualization/VP1GeometrySystems/src/VP1GeometrySystem.cxx
+++ b/GeoModelVisualization/VP1GeometrySystems/src/VP1GeometrySystem.cxx
@@ -1126,11 +1126,17 @@ double VP1GeometrySystem::Imp::inclusiveMass(const PVConstLink& pv) {
 
   GeoVolumeCursor av(pv);
   while (!av.atEnd()) {
-    mass += inclusiveMass(av.getVolume());
-    mass -= volume(av.getVolume())*density;
+    std::string materialName=av.getVolume()->getLogVol()->getMaterial()->getName();
+    
+    if (QString(materialName.c_str()).endsWith("Ether") || QString(materialName.c_str()).endsWith("HyperUranium")) {
+      // Do nothing.  These are not real volumes. 
+    }
+    else {
+      double delta =  inclusiveMass(av.getVolume()) -  (volume(av.getVolume())*density);
+      mass += delta;
+    }
     av.next();
   }
-
   return mass;
 }
 
diff --git a/GeoModelVisualization/VP1GeometrySystems/src/settings_interactions_form.ui b/GeoModelVisualization/VP1GeometrySystems/src/settings_interactions_form.ui
index 7ebd63257a292f3e7c4792101c2f59e044a80359..16ab476e81a2b8f3bcc070df28f4b14164033208 100644
--- a/GeoModelVisualization/VP1GeometrySystems/src/settings_interactions_form.ui
+++ b/GeoModelVisualization/VP1GeometrySystems/src/settings_interactions_form.ui
@@ -77,7 +77,7 @@ p, li { white-space: pre-wrap; }
 &lt;p style=&quot; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;&quot;&gt;In the case where either the selected volume or one its daugthers (or daughters daughters, etc.), is defined as a boolean volume, this might not give an entirely accurate result.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
         </property>
         <property name="text">
-         <string>Mass (unreliable)</string>
+         <string>Mass (slow!)</string>
         </property>
        </widget>
       </item>