Second Bank of the United States

Independence National Historical Park
Philadelphia, Pennsylvania

Scanning electron micrographs (SEM) of collected samples and X-ray (EDS) analysis provided analysis changes in mineral content.

 

Selective analysis of Pennsylvania Blue marble from the north portico was conducted in 1999, allowing confirmation of the mineral composition and black gypsum crusts, and identification of previous waterproof coatings. Scanning electron micrographs (SEM) of collected samples from protected areas showed a gypsum-rich blistered crust on the surface of the marble, and EDS analysis confirmed a Silicon-rich coating still prevalent in protected areas.

 

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