Maryland Department of Natural Resources

Critical Minerals - Samples Analyzed for Geochemistry

GENERAL OVERVIEW

Rock samples from existing Maryland Geological Survey collections, representative of locations identified as having potential for hosting critical minerals, were submitted to the US Geological Survey for geochemical analysis. Each sample record contains sample description, location, and results of analyses including major elements as well as minor and trace elements.

PURPOSE

Geochemical data from these samples contributes to understanding of critical mineral resources in Maryland and the U.S.

STATUS

As part of the USGS National Geologic and Geophysical Data Preservation Program (NGGDPP) FY2023 and FY2024 funding opportunities, the Maryland Geological Survey prepared 50 rock samples in FY23 and 149 rock samples in FY24 for analysis by the U.S. Geological Survey, which is providing analyses for major elements and a select 61-element list to support minor and trace element analyses including the rare earth elements. Maryland samples came from existing collections and are representative of locations identified as having potential for hosting critical minerals in four physiographic provinces: the Appalachian Plateaus, Ridge and Valley, Piedmont, and Coastal Plain (Figure 1). The Maryland Geological Survey prepared an inventory of the samples, their source location and description.

As part of the FY24 NGGDPP activities, chromite host rock samples from two Maryland mine areas, Bare Hills and Soldiers Delight, were sent for geochemical analysis (Figures 2 and 3). Chromite was designated Maryland’s state mineral in June 2025, honoring its unique occurrence and mining and production history in Maryland. The Bare Hills sample is representative of the first chromite found in Maryland and occurs in lode, or massive, form, with chromium-bearing clinochlore and talc mineralization. The Soldiers Delight sample is disseminated “bird’s eye” chromite grains within massive serpentinite.

Information about this collection was submitted to the online Registry of Scientific Collections (ReSciColl) for the national program (see link below). It is expected that sample information will link to the USGS laboratory results, when available: (https://webapps.usgs.gov/rescicoll/collections.html?collection=66d216a1a984c476c4fc58e7&organization=4f4e4761e4b07f02db47dfca) .

CRITICAL MINERALS SAMPLE COLLECTION INQUIRIES

For inquiries regarding the MGS Critical Minerals Collection, please contact:
Ms. Rebecca Kavage Adams – 410-554-5553, rebecca.adams@maryland.gov

ACKNOWLEDGEMENTS

The work described above was funded in part by grants awarded in 2023 and 2024 by the U.S. Geological Survey (USGS) National Geological and Geophysical Data Preservation Program (NGGDPP) (grant numbers G23AP00430 and G24AP00292).

Location map of Maryland Potomac terrane and five quadrangles from which samples are sourced for the FY2023 grant.
Figure 1. Source locations of samples submitted for chemical analyses as part of the NGGDPP FY2023 and FY2024 funding opportunities.
Location map of Maryland Potomac terrane and five quadrangles from which samples are sourced for the FY2023 grant.
Figure 2. Examples of chromite forms in host rock. Black portions of the rocks shown are chromite; lighter colors are other minerals and/or rock material.
Location map of Maryland Potomac terrane and five quadrangles from which samples are sourced for the FY2023 grant.
Figure 3. Location of Soldiers Delight and Bare Hills chromite samples sent for geochemical analysis NGGDPP FY24 shown on a portion of The Critical Mineral Occurrence Potential Map of Maryland (NGGDPP FY19).