1) Fine-grained stone that can be worked easily by the masons.
1367 ‘providing him with … stones called frestanes’, York
1409 et pro frestane empto de custodibus fabricć Beatć Marić, Beverley
1453 ad fabricam unius honestć fenestrć de frestone et vitro, Hull. The glossary in The Fabric Rolls of York Minster quotes firstan and fyrestane as examples but these might be ‘firestone’ in the sense of stone resistant to fire.