Hi,
that is correct, all the telescopes manufacturers mentioned buy their fluorite crystal elements finished from Canon Optron - so did Vixen.
LZOS has the capabilities for fluorite too but very rarely does actually use it in in instruments for the civilian market:
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Zeiss Jena pioneered the use of CaF2 crystal independently from Takahashi with their APQ oiled triplet lenses (and found an ingenious solution for avoiding the problems with surface quality and coating of fluorite elements). Dr. Pudenz, one of the original APQ designers seems to be working with some german telescope shop to make a modern version of oiled fluorite triplet...
Astro Physics has in the past worked with fluorite (the original f5 Stowaway).
TEC makes oiled triplets with a fluorite element.
Joachim