[time-nuts] Is there anything better than a crystal oscillator?

[Peter Vince]

Over the years, better and better long-term accuracy has been 
achieved with various "atomic" references, but if I understand 
correctly, the actual oscillating element is still a quartz crystal, 
albeit in a tightly controlled loop.  None-the-less, from discussions 
in this group I believe that the short-term noise and stability is 
still mainly that of the quartz crystal, and its associated 
electronics.  Is there anything better than quartz?  Did I hear 
something about sapphire?

	Regards,

		Peter Vince  (London, England)