diff --git a/google-map-marker.html b/google-map-marker.html
index fb789a3..6522e59 100644
--- a/google-map-marker.html
+++ b/google-map-marker.html
@@ -207,8 +207,8 @@
            * @type string|google.maps.Icon|google.maps.Symbol
            */
           icon: {
-            type: Object,
-            value: null,
+            type: String,
+            value: '',
             observer: '_iconChanged'
           },