The crystal may already be a super in the sense that it might have two mutant copies of the same gene. It may be that mom has an allele of mojave - a different mutation of that gene (it's looking like lesser, phantom, Vin russo, and perhaps others are also mutations of that same gene). The technical term for different versions of the same gene is allele. So far most allele pairs we have seen are normal and one mutant version like normal for albino and albino mutant versions of the gene at the albino location. However, it's looking like this locus is for some reason full of different mutant versions.
If the genes that make up crystal are an allele pair then crystal X crystal would produce eggs each with 25% chance of being super (homozygous) mojave, 50% chance of being crystal, and 25% chance of being whatever the homozygous version of mom turns out to be. There really wouldn't be a super crystal per say as it couldn’t have more than two copies total from all the different versions of the gene.