diff --git a/libs/geom/include/psemek/geom/quaternion.hpp b/libs/geom/include/psemek/geom/quaternion.hpp
index c794ce96..67d601d8 100644
--- a/libs/geom/include/psemek/geom/quaternion.hpp
+++ b/libs/geom/include/psemek/geom/quaternion.hpp
@@ -199,4 +199,10 @@ namespace psemek::geom
 		}
 	}
 
+	template <typename T>
+	std::ostream & operator << (std::ostream & os, quaternion<T> const & q)
+	{
+		return os << q.coords;
+	}
+
 }