diff --git a/src/ObjCommon/Material/JsonMaterial.h.template b/src/ObjCommon/Material/JsonMaterial.h.template
index f3fbb66f..6afb6b0a 100644
--- a/src/ObjCommon/Material/JsonMaterial.h.template
+++ b/src/ObjCommon/Material/JsonMaterial.h.template
@@ -509,7 +509,6 @@ namespace GAME
         uint8_t maxStreamedMips;
 #elif defined(FEATURE_T6)
         unsigned layeredSurfaceTypes;
-        unsigned hashIndex;
         unsigned surfaceFlags;
         unsigned contents;
         uint8_t probeMipBits;
@@ -534,7 +533,6 @@ namespace GAME
         maxStreamedMips,
 #elif defined(FEATURE_T6)
         layeredSurfaceTypes,
-        hashIndex,
         surfaceFlags,
         contents,
         probeMipBits,
diff --git a/src/ObjLoading/Material/JsonMaterialLoader.cpp.template b/src/ObjLoading/Material/JsonMaterialLoader.cpp.template
index 21c32982..69ceb3ef 100644
--- a/src/ObjLoading/Material/JsonMaterialLoader.cpp.template
+++ b/src/ObjLoading/Material/JsonMaterialLoader.cpp.template
@@ -420,7 +420,6 @@ namespace
             material.info.surfaceTypeBits = jMaterial.surfaceTypeBits;
 #ifdef FEATURE_T6
             material.info.layeredSurfaceTypes = jMaterial.layeredSurfaceTypes;
-            material.info.hashIndex = static_cast<uint16_t>(jMaterial.hashIndex);
             material.info.surfaceFlags = jMaterial.surfaceFlags;
             material.info.contents = jMaterial.contents;
 #endif
diff --git a/src/ObjWriting/Game/T6/Material/DumperMaterialT6.cpp b/src/ObjWriting/Game/T6/Material/DumperMaterialT6.cpp
index c90c2eb7..9f193037 100644
--- a/src/ObjWriting/Game/T6/Material/DumperMaterialT6.cpp
+++ b/src/ObjWriting/Game/T6/Material/DumperMaterialT6.cpp
@@ -30,5 +30,6 @@ void AssetDumperMaterial::DumpAsset(AssetDumpingContext& context, XAssetInfo<Mat
 
     const auto* material = asset->Asset();
     assert(material->info.gameFlags < 0x8000);
+    assert(material->info.hashIndex == 0);
     DumpMaterialAsJson(*assetFile, *material, context);
 }
diff --git a/src/ObjWriting/Material/JsonMaterialWriter.cpp.template b/src/ObjWriting/Material/JsonMaterialWriter.cpp.template
index 00cc2b43..fdbec537 100644
--- a/src/ObjWriting/Material/JsonMaterialWriter.cpp.template
+++ b/src/ObjWriting/Material/JsonMaterialWriter.cpp.template
@@ -315,7 +315,6 @@ namespace
             jMaterial.surfaceTypeBits = material.info.surfaceTypeBits;
 #ifdef FEATURE_T6
             jMaterial.layeredSurfaceTypes = material.info.layeredSurfaceTypes;
-            jMaterial.hashIndex = material.info.hashIndex;
             jMaterial.surfaceFlags = material.info.surfaceFlags;
             jMaterial.contents = material.info.contents;
 #endif
diff --git a/test/ObjLoadingTests/Game/T6/Material/LoaderMaterialT6Test.cpp b/test/ObjLoadingTests/Game/T6/Material/LoaderMaterialT6Test.cpp
index 2596dc78..2d797315 100644
--- a/test/ObjLoadingTests/Game/T6/Material/LoaderMaterialT6Test.cpp
+++ b/test/ObjLoadingTests/Game/T6/Material/LoaderMaterialT6Test.cpp
@@ -62,7 +62,6 @@ namespace
         "10",
         "CASTS_SHADOW"
     ],
-    "hashIndex": 0,
     "layeredSurfaceTypes": 536870925,
     "probeMipBits": 0,
     "sortKey": 4,
diff --git a/test/ObjWritingTests/Game/T6/Material/DumperMaterialT6Test.cpp b/test/ObjWritingTests/Game/T6/Material/DumperMaterialT6Test.cpp
index 4c6e5f50..a8704d6d 100644
--- a/test/ObjWritingTests/Game/T6/Material/DumperMaterialT6Test.cpp
+++ b/test/ObjWritingTests/Game/T6/Material/DumperMaterialT6Test.cpp
@@ -282,7 +282,6 @@ namespace
         "10",
         "CASTS_SHADOW"
     ],
-    "hashIndex": 0,
     "layeredSurfaceTypes": 536870925,
     "probeMipBits": 0,
     "sortKey": 4,