diff --git a/coord/ops.hpp b/coord/ops.hpp
index 7bcf8507..d2c77c5d 100644
--- a/coord/ops.hpp
+++ b/coord/ops.hpp
@@ -50,6 +50,20 @@ namespace util {
             template <size_t,typename> class B
         >
         using result_t = typename result<A,B>::type;
+
+
+        //---------------------------------------------------------------------
+        template <template <size_t,typename> class K>
+        struct has_scalar_op : public std::false_type { };
+
+        template <> struct has_scalar_op<colour>     : public std::true_type { };
+        template <> struct has_scalar_op<extent>     : public std::true_type { };
+        template <> struct has_scalar_op<point>      : public std::true_type { };
+        template <> struct has_scalar_op<quaternion> : public std::true_type { };
+        template <> struct has_scalar_op<vector>     : public std::true_type { };
+
+        template <template <size_t,typename> class K>
+        constexpr auto has_scalar_op_v = has_scalar_op<K>::value;
     }
 
     template <template <size_t,typename> class> struct is_coord : std::false_type { };
@@ -129,7 +143,7 @@ namespace util {
         typename U,                                     \
         template <size_t,typename> class K,             \
         typename = std::enable_if_t<                    \
-            is_coord_v<K>,void                          \
+            coord::has_scalar_op_v<K>, void             \
         >                                               \
     >                                                   \
     constexpr                                           \
@@ -149,7 +163,7 @@ namespace util {
         typename U,                                     \
         template <size_t,typename> class K,             \
         typename = std::enable_if_t<                    \
-            is_coord<K>::value,void                     \
+            coord::has_scalar_op_v<K>,void              \
         >                                               \
     >                                                   \
     constexpr                                           \
diff --git a/quaternion.cpp b/quaternion.cpp
index 8a3919b5..b54b9e8d 100644
--- a/quaternion.cpp
+++ b/quaternion.cpp
@@ -137,34 +137,6 @@ util::operator/ (const quaternion<S,T> a, const quaternion<S,T> b)
 template quaternion<4,float> util::operator/ (quaternion<4,float>, quaternion<4,float>);
 
 
-///////////////////////////////////////////////////////////////////////////////
-template <size_t S, typename T>
-quaternion<S,T>
-util::operator* (const quaternion<S,T> q, const T t)
-{
-    return {
-        q.w * t,
-        q.x * t,
-        q.y * t,
-        q.z * t
-    };
-}
-
-
-//-----------------------------------------------------------------------------
-template <size_t S, typename T>
-quaternion<S,T>
-util::operator/ (const quaternion<S,T> q, const T t)
-{
-    return {
-        q.w / t,
-        q.x / t,
-        q.y / t,
-        q.z / t
-    };
-}
-
-
 ///////////////////////////////////////////////////////////////////////////////
 template <size_t S, typename T>
 util::matrix4<T>
diff --git a/quaternion.hpp b/quaternion.hpp
index 1244712a..9565c356 100644
--- a/quaternion.hpp
+++ b/quaternion.hpp
@@ -55,11 +55,13 @@ namespace util {
         static const quaternion IDENTITY;
     };
 
-    template <size_t S, typename T> quaternion<S,T> operator* (const quaternion<S,T>, const quaternion<S,T>);
-    template <size_t S, typename T> quaternion<S,T> operator/ (const quaternion<S,T>, const quaternion<S,T>);
+    template <size_t S, typename T>
+    quaternion<S,T>
+    operator* (const quaternion<S,T>, const quaternion<S,T>);
 
-    template <size_t S, typename T> quaternion<S,T> operator* (const quaternion<S,T>, const T);
-    template <size_t S, typename T> quaternion<S,T> operator/ (const quaternion<S,T>, const T);
+    template <size_t S, typename T>
+    quaternion<S,T>
+    operator/ (const quaternion<S,T>, const quaternion<S,T>);
 
     typedef quaternion<4,float> quaternionf;