Fitting a limestone composite mantelpiece with an open fire

[Maysiegirl]

Hello, wondered if anyone has the information I need please.
I bought a 'limestone' mantelpiece from an online auction site only to find out it is actually a limestone composite material. This wasn't a worry to me as I liked the style of it. A friend has since told me he believes it should not be fitted to an open fire. We burn mostly wood, occasionally coal and I have to admit the fire does throw out some heat. Now, do I fit it anyway as I have yet to find any confirmation he is right on the internet or will it cause problems if I do? Also (sorry lots of queries) what sort of problems would it cause? It is the mantelpiece that's composite so wouldn't be in direct contact with the actual fire.
Hope someone has the answers I need.

 

[Pigeon85]

After a quick bit of research on good ole wiki, it says it would not be affected by temperatures below 150c if that's any help to you.

 

[WalksWithTurkeys]

Marble composites are I think a mix of marble fragments and glue, and it is the glue that cannot stand high temperatures. I think that is also true of limestone composites. Why not use a thermometer to measure the actual temperature around the opening? Obviously you need a special thermometer which has a suitable range, not a room one.

I considered a composite surround and hearth and the manufacturers state that they are not suitable for use with a stove, even though it does not get that hot near a stove. It might be that when a coal or log falls out, the temperature is high.

 

[Maysiegirl]

Many thanks for the very helpful replies. 150deg seems very hot and I would fit a cast iron insert or similar. Not sure where I would get my hands on a suitable thermometer....my concern would be that if I ask a trade professional I may be led to buy a new unit unecessarily, if you know what I mean!
Thanks again for the info.