Portland Stone, from the United Kingdom, and Larvikite, from Norway, Estremoz marble from Portugal,… Up to fifteen stones were reviewed and approved as GHSR (up to December 2018). Several are being processed at the moment to be consider as candidates and are expecting last steps to achieve the designation as GHSR.
18Sep

Can you tell me when Portland stone and Welsh Slate were designated as GHSRs, please?
Sorry for the delay in replying. I rarely use this web page for comments, as I rarely have comments through this media.
Portland stone was designated in 2017 and Welsh slate in 2018. All the information is in the HSS documents (e.g. circulars, newsletters, etc…)
Best regards.