Does touching a rosary to a saint's tomb/reliquary make the rosary a 3rd class relic, or do you have to touch it directly to their relics?
I believe that for something to be a third class relic, it must directly touch a second- or first- class relic (so either touch a body part of a saint; a part of the True Cross, Manger, etc; or an item of clothing or an object used in prayer of a saint). So just touching the tomb/reliquary would probably not get the job done
The problem is that the Church does not have any documentation regarding third class relics and with so many people wanting relics now the whole thing has got out of hand.
Traditionally a first class relic is a part of the saint’s body, a second class relics is an item worn or used by the saint, and a third class relic is an item touched only to a first class relic (not to a second class relic).
A first-class relic is typically housed within a container affixed with a seal which is not supposed to be broken (i.e., to help guarantee the authenticity of the relic within). Therefore, it is not possible to touch objects directly to a first-class relic without breaking the seal and removing the relic from the container. In light of all this, I think it suffices to simply touch an object to a reliquary in order to be considered a third-class relic. I actually witnessed one of the former pastors of the National Shrine of St. Dymphna in Massillon, Ohio blessing medals of St. Dymphna and then touching them to a reliquary containing a first-class relic of this saint. The first-class relic remained encased in the reliquary the entire time. The medals were then labeled as third-class relics.
I do not know about touching an object to the tomb of a saint, but I think an argument could be made supporting this idea. I say this because I once heard that in the case of a saint whose remains' location is unknown it suffices to touch an object to a shrine dedicated to him / her for that object to be considered a third-class relic. If that is true then it seems all the more reasonable to presume the same happens to an object touched to the tomb of a saint, seeing as the remains of the saint are actually present. The tomb, after all, could be consider a kind of reliquary.
Nevertheless, I do not know of any actual Church documents stating what I've presented here.
A relic of St Faustina (a piece of bone - a first class relic) was taken to the USA and the container was opened to allow people to touch a cloth to the bone thereby making the cloth a third class relic.
Since you cannot access the relic itself (bones, or whatsoever) due to being placed in a reliquary or in the tomb, it is considered a third-class relic.