Marble’s Reagent, 500 mL



Marble’s Reagent (AKA Marble’s etch) is a metallographic etchant primarily used for micro-etching 300 series stainless steels, nickel, and cobalt-based superalloys. This etchant darkens austenitic grains, attacks sigma phases, and reveals grain flow. On a side note, scratch marks resulting from sample preparation become apparent when treated with this reagent. Marble’s Reagent is formulated with reagent-grade chemicals and is listed as formula number 25, “Marble’s,” in ASTM standard E407.

If you are looking for a macro-etching chemical for 304 or 316 welds, please try our stainless steel weld etch.

User Instructions:

  • Mirror polish the sample before etching.
  • Etch any corrosion-resistant alloy as soon as it’s polished, cleaned, and dried without delay. Otherwise, the metal surface will passivate.
  • Immerse or swab the sample for a few seconds to minutes.


Nalgene® Leakproof Bottle, HDPE.

316 stainless steel etched with Marble's Reagent

Additional information

Weight 1.5 lbs
Dimensions 4.4 × 3.5 × 6.5 in
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