Specific gravity (SG) is one of the base hydrometry units used for relative density. In most cases this is relative to the density of water, water therefore having a specific gravity of one (1).
http://www.haandbrygforum.dk/gallery/albums/userpics/10003/Hydrometer_brug_og_SG_tabeller..pdf
For example, a sample of sand having an absorption of 5% and a specific gravity of 2.63 has a bulk specific gravity saturated surface dry that is computed as follows: Gs(ssd) = (1 + 0.05) x 2.63 = 2.76.
https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_024034.pdf
For example, the specific gravity of a dry coarse aggregate (Gs) is 2.65. The unit weight of water is 62.4-lb/cu ft. The absolute volume of a 90-lb sample of the aggregate is:
https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_024034.pdf
The specific gravity of the cement is calculated to be 3.15. A commonly used water to cement ratio is 0.46, which means 46 grams of water to 100 grams of dry cement. 41 The results of the thickening time tests on the Consistometer.
http://www.oilproduction.net/files/Drilling_engineering.pdf
pdf for "specific gravity of water 62 4".(Page 1 of about 18 results)