Active job

Heat/Fire Resistant Floating Shelf

I am wanting a fire/heat resistant floating shelf put in above a gas fire to protect the tv which is on the wall above it. Have been told this should be either stone, hebel, granite etc. The length needs to be as long as gas fire (approx. 1067mm) and the thickness 40mm and measurement out from wall under tv approx. 140mm. This is a newly built house we brought which has all the tv connections above the gas fire (not something we designed and no it isn't good for a tv to be above a fire)