I read that care must be taken when selecting a germanium source because a toxic blend of germanium dioxide and vitamin C can be indistinguishable from germanium sesquioxide by any analytical methods. Is this true?

I’ve read this too. Actually this is more a statement of ignorance and ineptitude than anything else. Care should be taken when sourcing any product intended for consumption. Personally I would be terrified to purchase product from someone so lacking in technical ability that distinguishing a mixture of vitamin C and germanium dioxide from true germanium sesquioxide poses an insurmountable challenge. Go to our website and look up U.S. manufactured Organic Germanium and the seminar on Organic Germanium. The analytical section outlines numerous tests, most of which will readily detect such a fraud.