Mortar analysis starts with a petrographic examination so that all components may be identified through direct observation rather than inference. The photomicrograph here illustrates a residual particle of natural cement. The textures indicate a clay-rich dolomitic product consistent with most American cements of the 19th century. This information is passed on to the chemist so that a chemical procedure can be modified specifically for the identified mortar components. In this way, accurate partitioning of the individual components is ensured so that there is no guesswork when estimating original weight percentages.

A Highbridge chemist uses atomic absorption spectroscopy to measure the major elements of any binders identified in a historic mortar or stucco. These data are not only used to estimate mix designs but also to understand the physical properties of the mortar. Here, the nitrous oxide flame is used to determine soluble silica, an element associated with hydraulic binders. In this case, petrographic examination determined that a 19th century lime mortar was hydraulic in nature. By measuring the individual elements of the binder rather than simply determining the binder weight, the chemist is able to determine how hydraulic the lime was. This degree of detail cannot be gained from either simple acid digestion or x-ray diffraction analysis.