diff --git a/mlir/include/mlir/IR/StandardTypes.h b/mlir/include/mlir/IR/StandardTypes.h
--- a/mlir/include/mlir/IR/StandardTypes.h
+++ b/mlir/include/mlir/IR/StandardTypes.h
@@ -456,9 +456,7 @@
   using ShapedType::ShapedType;
 
   /// Return true if the specified element type is ok in a memref.
-  static bool isValidElementType(Type type) {
-    return type.isIntOrIndexOrFloat() || type.isa<VectorType, ComplexType>();
-  }
+  static bool isValidElementType(Type type);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast.
   static bool classof(Type type);
diff --git a/mlir/lib/IR/StandardTypes.cpp b/mlir/lib/IR/StandardTypes.cpp
--- a/mlir/lib/IR/StandardTypes.cpp
+++ b/mlir/lib/IR/StandardTypes.cpp
@@ -363,6 +363,16 @@
 // BaseMemRefType
 //===----------------------------------------------------------------------===//
 
+/// Return true if the specified element type is ok in a memref.
+bool BaseMemRefType::isValidElementType(Type type) {
+  // Note: Non standard/builtin types are allowed to exist within memref
+  // types. Dialects are expected to verify that memref types have a valid
+  // element type within that dialect.
+  return type.isa<ComplexType, FloatType, IntegerType, OpaqueType, VectorType,
+                  IndexType>() ||
+         !type.getDialect().getNamespace().empty();
+}
+
 unsigned BaseMemRefType::getMemorySpace() const {
   return static_cast<ImplType *>(impl)->memorySpace;
 }
diff --git a/mlir/lib/Parser/TypeParser.cpp b/mlir/lib/Parser/TypeParser.cpp
--- a/mlir/lib/Parser/TypeParser.cpp
+++ b/mlir/lib/Parser/TypeParser.cpp
@@ -217,8 +217,7 @@
     return nullptr;
 
   // Check that memref is formed from allowed types.
-  if (!elementType.isIntOrIndexOrFloat() &&
-      !elementType.isa<VectorType, ComplexType>())
+  if (!BaseMemRefType::isValidElementType(elementType))
     return emitError(typeLoc, "invalid memref element type"), nullptr;
 
   // Parse semi-affine-map-composition.
diff --git a/mlir/test/IR/parser.mlir b/mlir/test/IR/parser.mlir
--- a/mlir/test/IR/parser.mlir
+++ b/mlir/test/IR/parser.mlir
@@ -78,6 +78,9 @@
 // CHECK: func @memrefs(memref<1x?x4x?x?xi32, #map{{[0-9]+}}>, memref<8xi8>)
 func @memrefs(memref<1x?x4x?x?xi32, #map0>, memref<8xi8, #map1, #map1>)
 
+// CHECK: func @memref_quant_element(memref<3x!quant.uniform<u8:f32, 1.000000e+00:66>>)
+func @memref_quant_element(memref<3x!quant.uniform<u8:f32, 1.0:66>>)
+
 // Test memref affine map compositions.
 
 // CHECK: func @memrefs2(memref<2x4x8xi8, 1>)