Molecular Structure:

Molecular Formula: H₄CaO₆S
Molecular Weight: 172.1712
IUPAC Name: Calcium sulfate dihydrate
Synonyms of Calcium sulfate dihydrate (CAS NO.10101-41-4): Annaline ; C.I. 77231 ; Calcium sulfate dihydrate (CaSO4.2H2O ; Compactrol ; Light spar ; Magnesia White ; Mineral White ; Native calcium sulfate ; Precipitated calcium sulfate ; Satin spar ; Satinite ; Sulfuric acid, calcium(2+) salt, dihydrate ;Terra alba ; UNII-4846Q921YM ; Calcium(II) sulfate, dihydrate (1:1:2) ; Sulfuric acid, calcium salt (1:1), dihydrate
CAS NO: 10101-41-4
Classification Code: Agricultural Chemical ; Unspecified / Unclassified pesticide
Melting point: 128°C 
Enthalpy of Vaporization: 62.94 kJ/mol
Boiling Point: 330 °C at 760 mmHg
Vapour Pressure: 3.35E-05 mmHg at 25°C

  Calcium sulfate dihydrate (CAS NO.10101-41-4) (the half-water salt) can be made into wall plaster by the addition of a filler material such as asbestos, wood pulp, or sand. Without additions, it is plaster of Paris and is used for making casts and for plaster.

  Calcium sulfate occurs in large deposits throughout the world as its hydrate (gypsum; CaSO₄.2H₂O). When heated at moderate temperatures, Calcium sulfate dihydrate (CAS NO.10101-41-4) loses part of the water to form a semihydrate.
         CaSO₄.2H₂O → CaSO₄.1/2H₂O + 1 1/2H₂O
At higher temperatures, it loses all its water and becomes anhydrous calcium sulfate, or anhydrite.

Hazard Codes of Calcium sulfate dihydrate (CAS NO.10101-41-4): Xn
Risk Statements: 20/21/22-36/37/38 
R20/21/22: Harmful by inhalation, in contact with skin and if swallowed. 
R36/37/38: Irritating to eyes, respiratory system and skin.
Safety Statements: 22-24/25-36-26 
S22: Do not breathe dust. 
S24/25: Avoid contact with skin and eyes. 
S36: Wear suitable protective clothing. 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
WGK Germany: 1
RTECS: EW4150000
HS Code: 28332990