A grating interferometer enables the separation of phase and absorption profiles of bulk samples using high-efficiency hard X-ray (10–30 keV) and phase-stepping techniques. This method allows quantitative three-dimensional maps of the X-ray refractive index with sub-micron resolution. The interferometer is mechanically robust, requires minimal spatial coherence and monochromaticity, and can be scaled for large fields of view with moderate detector resolution. These features make it suitable for laboratory X-ray sources. The method uses a phase grating (G1) and an absorption grating (G2) to split and recombine X-ray beams, creating interference patterns that reveal phase shifts caused by objects. Phase-stepping techniques separate phase information from absorption and other noise. Tomographic reconstruction yields quantitative refractive index maps. The interferometer is largely achromatic, allowing efficient use of polychromatic radiation. The spatial resolution is limited by detector resolution, grating periods, and lateral shear from the beam splitter. The device is mechanically stable and easy to align, with minimal sensitivity to mechanical drift. The method has potential applications in medical, biological, and materials research, including neutron phase radiography. The setup is suitable for large field-of-view imaging and efficient use of broadband sources. The results demonstrate the feasibility of X-ray phase imaging with grating interferometers for quantitative and qualitative imaging.A grating interferometer enables the separation of phase and absorption profiles of bulk samples using high-efficiency hard X-ray (10–30 keV) and phase-stepping techniques. This method allows quantitative three-dimensional maps of the X-ray refractive index with sub-micron resolution. The interferometer is mechanically robust, requires minimal spatial coherence and monochromaticity, and can be scaled for large fields of view with moderate detector resolution. These features make it suitable for laboratory X-ray sources. The method uses a phase grating (G1) and an absorption grating (G2) to split and recombine X-ray beams, creating interference patterns that reveal phase shifts caused by objects. Phase-stepping techniques separate phase information from absorption and other noise. Tomographic reconstruction yields quantitative refractive index maps. The interferometer is largely achromatic, allowing efficient use of polychromatic radiation. The spatial resolution is limited by detector resolution, grating periods, and lateral shear from the beam splitter. The device is mechanically stable and easy to align, with minimal sensitivity to mechanical drift. The method has potential applications in medical, biological, and materials research, including neutron phase radiography. The setup is suitable for large field-of-view imaging and efficient use of broadband sources. The results demonstrate the feasibility of X-ray phase imaging with grating interferometers for quantitative and qualitative imaging.