ForMatter/Finishes/stone_finish/Flamed stone finish
finish_stone_flamed

Flamed stone finish

stone_finish · textured · thermal finish, flame-textured granite, exfoliated

An oxy-acetylene torch passed across the face of a granite slab — the differential thermal expansion of the quartz and feldspar crystals pops the surface into a coarse, slip-resistant texture. The classic finish on granite paving, building-base courses, exterior steps. Reads as a deep matte, deeply textured, almost geological surface.

Oxy-acetylene or oxy-propane flame at ~3000 °C passed across a wet stone surface. Quartz crystals (CTE 7 × 10⁻⁶/°C) and feldspar / mica (CTE 2–4 × 10⁻⁶/°C) expand at different rates; the differential exfoliates the surface in a 2–6 mm-deep coarse texture. Color reads slightly warmer / paler than polished (heat alters surface mineral chemistry, calcines fines). Slip-coefficient (BCRA / DIN 51097) goes from CL 0.3–0.5 polished to 0.7–0.9 flamed — the standard spec for outdoor steps and pool surrounds. Best on coarse-grained igneous stone (granite, basalt); won't work on fine-grained or calcareous (marble cracks; limestone calcines).

character — deep matte, coarse open-pore texture, paler than polished, geological-reading.

Finish properties

  • leveltextured
  • subcategorythermal-shock surface
  • Ra (µm)4000.0
  • applies tostone

Incompatibilities

  • marble, limestone, travertine — calcareous stone calcines or cracks under torch
  • fine-grained stone where mineral CTE delta is small
Pairs with materials

Second life

reversibilityzero on the existing stone — texture is geometric, present in the substrate. Re-finishing requires removing material to reach a different finish.
blocks substrate recyclingno
renewabilitymoderate — most stone finishes can be re-applied (re-honing, re-flaming) at the cost of minor material loss; field-renewability for indoor surfaces, shop-renewability for outdoor.

Marble Institute of America / Natural Stone Institute care-and-finish guides; ASTM C1242 dimension stone terminology.

Citations