French stone term for a hard, difficult stone liable to spall or burst unpredictably under the tool.
Fier describes a stone that is hard and resistant to working and has a tendency to break or spall unpredictably under the tools. For the sculptor, recognizing a pierre fière affects tool choice, striking force, edge safety, and expectations for detail.
Etymology
French quarry and stone-working vocabulary.
References
https://www.pierres-info.fr/glossaire/index.html