<Serializable()> _
Class Test
    Private c As Color
 
    Public Property cl() As Color
        Get
            Return c
        End Get
        Set(ByVal value As Color)
            c = value
        End Set
    End Property
End Class

        Dim t As New Test
        t.cl = Color.FromArgb(123, 45, 67)
 
        Dim xf As New XmlSerializer(GetType(Test))
        Dim sb As New StringBuilder
        xf.Serialize(New StringWriter(sb), t)
        MessageBox.Show(sb.ToString)

<?xml version="1.0" encoding="utf-16"?>
<Test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" _
  xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <cl />
</Test>