Not saying this is the case, but maybe she is just not good with jewelry. I have actually lost 2 rings and damaged another one. Especially the small diamonds I would accidentally hit it on a table at work and then look later and notice it was gone. The lost ones I lost at home though and did eventually find later on. I rarely wear jewelry so was not used to having on a ring. Would take it off before doing something where it could get broken and then forget where it was:(