Chemical formula of gypsum is CaSo4.2H2O.
Physical Properties of Gypsum:
| Properties | Details |
| Cleavage | Perfect, parallel to the basal plane |
| Color | Colorless to white, may have shades of yellow or gray |
| Crystal System | Monoclinic |
| Density | 2.3 grams per cubic centimeter (g/cm³) |
| Hardness | 2 on the Mohs scale of mineral hardness |
| Luster | Vitreous to pearly |
| Refractive Index | 1.52 to 1.54 |
| Solubility | Insoluble in water |
| Specific Gravity | 2.2 to 2.3 |
| Streak | White |
| Transparency | Translucent to transparent |
Chemical Properties of Gypsum:
| Property | Details |
| Chemical Formula | CaSO₄·2H₂O |
| Composition | Calcium sulfate dihydrate (hydrated calcium sulfate) |
| Dehydration Temperature | 120°C (248°F) |
| Flammability | Non-flammable |
| Hygroscopicity | Moderately hygroscopic |
| pH | Slightly acidic (pH 5.5 to 6.5) |
| Reactivity | Reacts with strong acids to form calcium sulfate |
| Solubility | Soluble in water at room temperature |
| Thermal Conductivity | Low |
Reaction of gypsum
Alkali metal
| Alkali metal | Reaction with calcium oxide | Reaction with sulfur trioxide |
| Lithium (Li) | CaO + 2Li react and changes into Li2O + Ca | Nill |
| Sodium (Na) | CaO + 2Na react and changes into Na2O + Ca | Na2SO4 + 10Na react and changes into 6Na2O + SO2 |
| Potassium (K) | CaO + 2K react and changes into K2O + Ca | K2SO4 + 10K react and changes into 6K2O + SO2 |
| Rubidium (Rb) | CaO + 2Rb react and changes into Rb2O + Ca | Rb2SO4 + 10Rb react and changes into 6Rb2O + SO2 |
| Cesium (Cs) | CaO + 2Cs react and changes into Cs2O + Ca | Cs2SO4 + 10Cs react and changes into 6Cs2O + SO2 |
Alkaline Earth Metal
| Alkaline Earth Metal | Reaction |
| Beryllium (Be) | Nill |
| Magnesium (Mg) | CaSO4·2H2O + Mg react and changes into MgSO4·2H2O + Ca |
| Calcium (Ca) | Nill |
| Strontium (Sr) | Nill |
| Barium (Ba) | CaSO4·2H2O + Ba react and changes into BaSO4 + Ca(OH)2 |
Transition Metal
| Transition Metal | Reaction with calcium oxide | Reaction with sulfur trioxide |
| Iron (Fe) | CaO + Fe react and changes into FeO + Ca | Nill |
| Copper (Cu) | CaO + Cu react and changes into CuO + Ca | Nill |
| Silver (Ag) | CaO + 2Ag react and changes into Ag2O + Ca | Nill |
| Gold (Au) | CaO + 2Au react and changes into Au2O + Ca | Nill |
| Platinum (Pt) | CaO + Pt react and changes into PtO + Ca | Nill |
Non-Transition Metal
| Non-Transition Metal | Reaction |
| Aluminum (Al) | CaSO4·2H2O + 2Al react and changes into Al2(SO4)3 + Ca(OH)2 |
| Zinc (Zn) | CaSO4·2H2O + Zn react and changes into ZnSO4 + Ca |
| Lead (Pb) | CaSO4·2H2O + Pb react and changes into PbSO4 + Ca |
| Tin (Sn) | CaSO4·2H2O + Sn react and changes into SnSO4 + Ca |
| Antimony (Sb) | CaSO4·2H2O + 2Sb react and changes into Sb2(SO4)3 + Ca |
Non-Metal Element
| Non-Metal Element | Reaction |
| Carbon (C) | CaSO4·2H2O + 2C react and changes into 2CO + SO2 + Ca(OH)2 |
| Phosphorus (P) | CaSO4·2H2O + 2P react and changes into 2H3PO4 + Ca |
| Sulfur (S) | CaSO4·2H2O + S react and changes into CaS + 2H2O |
| Chlorine (Cl) | CaSO4·2H2O + 2Cl react and changes into CaCl2 + H2SO4 |
| Fluorine (F) | Nill |
Metalloid Element
| Metalloid Element | Reaction |
| Boron (B) | CaSO4·2H2O + 2B react and changes into B2O3 + Ca(HSO4)2 + 2H2O |
| Silicon (Si) | Nill |
| Germanium (Ge) | Nill |
| Arsenic (As) | CaSO4·2H2O + As2O3 react and changes into Ca3(AsO4)2 + 2SO2 + 2H2O |
| Antimony (Sb) | CaSO4·2H2O + 2Sb react and changes into Sb2(SO4)3 + Ca |