diff --git a/id.go b/id.go
index 180070f..9f69714 100644
--- a/id.go
+++ b/id.go
@@ -19,6 +19,10 @@ func NewID() *ID {
 func (i *ID) Check() error {
 	if i.URI == "" {
 		return errors.New("uri element of id empty")
+	} else {
+		if !isValidURI(i.URI) {
+			return fmt.Errorf("uri element %v of id not correctly formatted", i.URI)
+		}
 	}
 
 	return nil