diff --git a/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs b/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs
index 45d73a65bfa4..3035117b9e53 100644
--- a/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs
+++ b/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs
@@ -207,8 +207,11 @@ public override Stream GetManifestResourceStream(Type type, string name)
                 throw new ArgumentNullException(nameof(type));
 
             string nameSpace = type?.Namespace;
-            string delimiter = (nameSpace != null && name != null) ? Type.Delimiter.ToString() : null;
-            string resourceName = string.Concat(nameSpace, delimiter, name);
+
+            char c = Type.Delimiter;
+            string resourceName = nameSpace != null && name != null ?
+                string.Concat(nameSpace, new ReadOnlySpan<char>(ref c, 1), name) :
+                string.Concat(nameSpace, name);
 
             return GetManifestResourceStream(resourceName);
         }
diff --git a/src/System.Private.CoreLib/src/System/Resources/ManifestBasedResourceGroveler.cs b/src/System.Private.CoreLib/src/System/Resources/ManifestBasedResourceGroveler.cs
index fe95bf1c8f68..42b601336a55 100644
--- a/src/System.Private.CoreLib/src/System/Resources/ManifestBasedResourceGroveler.cs
+++ b/src/System.Private.CoreLib/src/System/Resources/ManifestBasedResourceGroveler.cs
@@ -330,8 +330,11 @@ private Stream CaseInsensitiveManifestResourceStreamLookup(RuntimeAssembly satel
             Debug.Assert(name != null, "name shouldn't be null; check caller");
 
             string nameSpace = _mediator.LocationInfo?.Namespace;
-            string delimiter = (nameSpace != null && name != null) ? Type.Delimiter.ToString() : null;
-            string resourceName = string.Concat(nameSpace, delimiter, name);
+
+            char c = Type.Delimiter;
+            string resourceName = nameSpace != null && name != null ?
+                string.Concat(nameSpace, new ReadOnlySpan<char>(ref c, 1), name) :
+                string.Concat(nameSpace, name);
 
             string canonicalName = null;
             foreach (string existingName in satellite.GetManifestResourceNames())