• journal_title：American Mineralogist
• Contributor：Fangfu Zhang ; Huifang Xu ; Hiromi Konishi ; Eric E. Roden
• Publisher：Mineralogical Society of America
• Date：2010-
• Format：text/html
• Language：en
• Identifier：10.2138/am.2010.3414
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：95
• issue：11-12
• firstpage：1650
• section：Articles

X-ray diffraction has been widely used in analyzing Ca-Mg carbonates. Compositions of biogenic and inorganic (Ca,Mg)CO₃ crystals are often calculated by comparing their d₁₀₄ values with published empirical curves. However, previous studies suggested that these curves do not apply to very high-Mg calcite and disordered dolomite. Based on synthesized high-Mg calcite and disordered dolomite, a new empirical curve between values of magnesian calcite d₁₀₄ and MgCO₃ content in the calcite-disordered dolomite solid-solution series is constructed. This new curve is consistent with the significant cell parameter changes accompanying the Mg-Ca cation disorder in dolomite, and it can help the characterization of the MgCO₃ content of both natural and synthetic magnesian calcite and disordered dolomite, especially for the mineral mixtures that are not suitable for other analysis methods.