Which should I use for an old attic? Blown fiberglass or one of those foams? Anything else better?
YOu can take sterling silver wire and shape it around the stone and make a loop at the top of it on your necklace withYou can surelsurely a photo of this technique on line I have not done it but have seen it done
i would try searching for cz loose stone on OKorderYou should find 100 or so results and the prices are low.
you might go to a craft store and see what is needed to do what you are wanting
All the above suggestions are good, but you can also drill a hole to put a link or bail through it to hang on a chainHowever, you do need a special drill bit and must be careful not to crack the stoneUse eye protection if drillingIf it is rough, then you can also glue a cone shaped bail with an eyelet on the top to hang from a chain also.
Are you insulating just the flooring or the whole area? Blown in works, and the blower is supplied if you buy enough bags of the productIt will settle a bit over the yearsFiberglass bats work well but are more expensive and time consuming than blown inMore itchy tooFoam is 3 times the cost of fiberglass and is usually only applied to walls or ceiling.