The dataset provides information on chromium concentrations extracted from rock samples collected at the Garfield SF site in New Jersey (USA). The data are discussed in Zhao et al. (2017). Chemical Geology, v. 474, p. 1-8. This dataset is associated with the following publication: Zhao, J., T. Al, S. Chapman, B. Parker, K. Mishkin, D. Cutt, and R. Wilkin. Determination of Cr(III) solids formed by reduction of Cr(VI) in a contaminated fractured bedrock aquifer: evidence for natural attenuation of Cr(VI). CHEMICAL GEOLOGY. Elsevier Science Ltd, New York, NY, USA, 474: 1-8, (2017).