Attenuated total reflection infrared spectroscopy was applied for qualitative and quantitative analysis of aragonite-group carbonates. This simple, fast, and accurate technique requires no sample preparation and can serve as a rapid alternative to X-ray diffraction. The novel aspect of this work is the development of calibration curves for quantifying strontianite and witherite in aragonite mixtures using absorbance ratios between  peaks, reducing variability from measurement conditions.