Minerals with a higher SG will settle below material with a lower sg over time. The specific gravity of all other materials are compared to water as a fraction heavier or fraction lighter density, no matter how small or large the fraction is. Standard guidelines are varied, but most saltwater aquarists have it at somewhere between 1.020 and 1.025 depending on if its a reef tank or a FOWLR (fish only with live rock). Back to The Mineral Gallery Buy Halite Here. Halite (/ ˈ h æ l aɪ t / or / ˈ h eɪ l aɪ t /), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride (Na Cl).Halite forms isometric crystals. Some fish only or fish only with live rock tank owners keep it on the lower end. Specific Gravity represents the amount of dissolved salt in the water. Sometimes, halite may form “hopper” crystals in which the outer edges of the cube faces have grown more rapidly than their centers, leaving cavernous faces. For example, ammonium nitrate has a specific gravity (sg) of 0.73 while dry ammonium sulphate has a sg of 1.13 (1130 kilograms/cubic meter). Specific gravity, ratio of the density of a substance to that of a standard substance. Solids and liquids are often compared with water at 4 C, which has a density of 1.0 kg per liter. Water has a specific gravity of 1.0. Gases are often compared with dry air, having a density of 1.29 grams per liter (1.29 ounces per … If a mineral has a specific gravity of 2.7, it is 2.7 times heavier than water. The specific gravity value is expressed upon how much greater the weight of the mineral is to an equal amount of water. SG or Specific Gravity is the ratio of the weight of any substance to that of pure water at temperature of 3.98°C(39.2°F) and standard atmospheric pressure. Specific Gravity: 2.1 Hardness (Mohs): 2 Cleavage: perfect in 3 directions Fracture: conchoidal Other Characteristics: salty taste Uses: food supplement, ice control, water softening, ore for sodium and chlorine Location: Great Salt Lake, Utah, Searles lake, California in the USA, Germany, France. This is important to note when actively seeking these minerals in the wild. Halite crystals are usually cubic. The specific gravity of a mineral determines how heavy it is by its relative weight to water. Halite is commonly found in massive and bedded aggregates as rock salt. It also occurs in coarse, crystalline masses or in granular and compact forms. note: Specific gravity of Halite = 2.16 g/cm 3: Photoelectric: PE Halite = 4.63 barns/electron U = PE Halite x ρElectron density = 9.59 barns/cm 3: Fermion index: Fermion index = 0 Boson index = 1: Radioactivity: Halite is not radioactive.