Sphinxstone

Columns in Mellon Auditorium built with Sphinxstone
Courtesy of Citadel DCA

Description

[Sphinx-Tone Acoustical Company] An acoustic Cast stone produced by the Sphinx-Tone Acoustical Company of Washington, D.C. In 1934, Sphinxstone was used in the construction of the Andrew W. Mellon Auditorium in Federal Triangle, Washington D.C., designed by architect Arthur Brown Jr. During restoration of the building, visual inspection of the deteriorated sections of the concrete blocks indicated the stones contain mollusk shells and white Portland cement. Samples extracted for testing are undergoing analysis in preparation for cleaning and repairs (2022).

Sphinxstone label

Additional images

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  Closeup of Sphinxstone column
  Courtesy of Citadel DCA

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  Closeup of Sphinxstone column base
  Courtesy of Citadel DCA

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  Closeup of Sphinxstone column base
  Courtesy of Citadel DCA

Resources and Citations

• Lynn Scott Paden, Citadel DCA contributed information, June 2022.
• Richard Pieper, 'The Maintenance, Repair and Replacement of Historic Cast Stone' NPS, Technical Briefs #42 Link