In the present work, the microscopic structure of an as-cast Zr43Cu43Al7Ag7 bulkmetallic glass (BMG) had been investigated in detail. The structure analyses are performed using the laboratory X-ray diffraction (XRD), high-energy synchrotron X-ray diffraction, and transmission-electron microscopy (TEM). The results from different techniques are compared and discussed. The specimen shows a typical amorphous hallo using the conventional laboratory XRD. However, tiny crystalline particles, roughly ≈10 nm in size, are found in the sample by the high-energy XRD as well as the TEM. The standard laboratory XRD measurement is not adequate to differentiate amorphous from a nano-composite phase. The high-energy XRD method is an essential technique to determine the glassy nature of a BMG.