Well, if I was Catholic, I’d probably keep it and use it. Alas, I am but an ignorant heathen, so the best I can do is try not to offend your god by accidentally doing inappropriate things to one of his sacred objects.
It makes me very happy to see such respectful interaction. My heart is warmed, and I am glad I’m not alone in my feelings regarding “objects of faith.” I get angry and disgusted when I read news articles about the desecration of houses of worship, theft of items therefrom, damage inflicted on the sacred grounds of cemetaries, etc. As I would not want anyone to insult my faith, none of those insults to the faiths of others would be acceptable to me. I do my best to protect those being harmed in daily life, and as a result, sometimes I am gifted with things like the rosary you received.
In the presence of such respect, there is no reason why “Heathens” (such as you and I, Gullveig) can’t keep a gift such as this, even if we find no personal “use” for it. A rosary (or other such object) does not have to be “used” to be respected and enjoyed. It seems this gift of a rosary came to you from someone’s heart. If it is a gift of love, then keep it. I keep my items in what is my personal “sacred space.” This may be a home altar, a devotional area, a bookcase containing photos or remembrances of your family tree, a steamer trunk in which private, meaningful items are kept hidden, etc. (Regarding rosaries in particular… similar items are being made by those who follow our paths. They are called prayer beads, Goddess beads, etc., and I possess some myself. I keep them with a Catholic rosary, a medal of Our Lady of Mt. Carmel, and other items from various different religions all of which I use as devotionals for that which is the sacred feminine.)
I wonder if your rosary has been blessed. (Some such items may not be blessed at first, as part of the remarkable experience of obtaining a special item could be the actual participation in the blessings itself,
i.e., holding it while the Priest blesses it, feeling his hand atop the believer’s hand, enjoying the atmosphere of a holy place - the Church - while the blessing is performed, all of which adds to its “specialness.”) Whether it’s blessed or not, offering such respect as you are doing under the circumstances is refreshing. I don’t think God/dess would be in the least offended by such positive efforts.
Namaste.