Stellerite Geode from India

Stellerite and Chalcedony from Deccan Traps, India.
 
 Rare mineral !
 Museum piece, unique !
 Ideal for connoisseurs looking for excellence , this Geode of  Stellerite will bring satisfaction.
 It deserves its place in the most refined collections or the most prestigious showcases .
 
 Origin: Deccan Traps, Bombay Mine, Mumbai District, India.
 Size: 12cm by 12cm by 6.5cm
 Chemical formula: Ca Al2 Si7 O18 7H2 O
 Crystal system: Orthorhombic
 Hardness Mohs scale: 3.5 to 4
 Definition: Stellerite is a mineral species of the group of silicates , of the family of zeolites . Very close to stilbite from which it differs by the substitution of aluminum by silicon in its formula. As with stilbite , crystals of stellerite can associate to form a structure resembling sheaves of wheat. Stellerite can form isolated spheres of 12 cm in diameter. Stellerite, however, remains less colored than stilbite .