Many thanks for your very helpful answers, joe! I suppose the calfskin would be less "luxurious" as compared to the lambskin. but I will try to search for the calfskin versions in the forum; to see the differences between the 2 types of leathers. I would check out the patent LDs as well. Am just not sure on the patent-don't want anything too shiny as my mom is in her 60s and I don't think she'll like a too shiny kind of bag.
thanks for correcting me on the term "caviar"
Calfskin can be very luxurious as well. In fact, Dior's new Diorissimo line of bags with an even higher price point than the Lady Dior is made of beautiful grained calfskin (akin to the Hermes Birkin).
The more recent calfskin versions of the Lady Dior are seasonal styles that are slightly different from the classic design. I have attached a picture of one below. The price of this calfskin version is higher than the lambskin version, but it also has hand-tied leather "bows" which add to the price.
My mom is the same about patent, and she's in her 60s as well, so I understand. In this case, then the lambskin will be the best choice. It isn't that delicate, and your mom will absolutely love it. May I suggest the black lambskin Lady Dior with the gold hardware? It looks very classy and elegant.