My late husband was a ‘fine woodworker’, I am not, but I have a 30 in X 12 in X 2 in slab of purple heart that I am hand carving for his headstone.

After I finish the headstone I was intending to varnish it with about 6 coats of marine spar varnish with a UV shield. Will this be OK and will it maintain the gorgeous purple tone when set outdoors? I realise I will be resanding and lightly revarnishing it once a year.

Also I have a small 1/4 in thick piece of  cocobolo that I want to stick on the purple heart slab before I varnish. Will white woodworker glue be OK?