A custom-built laboratory nuclear magnetic resonance (NMR) spectrometer was used to quantify the magnetite grade of 35 blended magnetite samples. The samples were approximately 2 g each and were mixed with quartz to a range of magnetite grades from approximately 10–80 wt per cent. Quantitative X-ray diffraction was also performed on these samples to independently determine the grade. An excellent linear correlation between magnetite grade as determined by quantitative X-ray diffraction, and NMR spin echo signal was achieved with 𝑅 =0.98 for the blended samples. An NMR spectrometer intended for use on a primary iron ore belt was built and two bulk samples from Braemar iron formation were measured. The spectrometer aperture was built to 1.2 m as a manageable scale for our laboratory and could measure over 70 kg of magnetite ore. The NMR spin echo signal as a function of the mass of magnetite present in the sensor was determined. An excellent correlation between magnetite mass and NMR spin echo signal was achieved for both bulk samples. A lower detection limit was inferred based on the results and was calculated to be 2.07 kg of pure magnetite in 50 sec of measurement time. As such, magnetic resonance of magnetite presents an excellent opportunity for bulk quantification or beneficiation processes.