The lady on the left, who is Russian Orthodox, can be seen wearing a chapel veil at the Vatican last Sunday. The mantilla is a lovely Judeo-Christian custom that takes a Spaniard to describe in toto:
"A real Spanish mantilla is a long lace veil that a lady wears overhead fixed by a high back comb. When you purchase it you have then to ask for the two elements: the veil and the back comb (in Spanish: "mantilla y peineta"). A mantilla could be: black, white or golden. Black mantilla is weared by wives, widows and for mourning and religious ceremonies related to Holy Week. White mantilla is weared only by girls, maiden ladies and brides. Golden mantilla can be worn both by wives and maiden ladies but in solemn occasions. I do not recommend you to buy a mantilla through internet. It is a very expensive item if good and you risk to waste your money if you do not make the right choice. Let me find out if there is still operating an old shop in Barcelona that used to sale nice and fine mantillas. I would ask for a catalogue and bring it you."