Dense solids, such as barite or hematite, which are added to a mud to increase its density, also known as weighting material. The concentration of high-gravity solids in a weighted mud is measured by the mud engineer daily using mud weight, retort data, chloride titration data and other information. Solids are reported as lbm/bbl or vol. %. The specific gravity of water is 1. 00, barite is 4. 20, and hematite 5. 505 g/cm³. Drill solids and other low-gravity solids are normally assumed to be 2. 60 g/cm³.