Clinozoisite is a mineral, a complex sorosilicate of calcium

Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 and aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 and is usually a grey green colour.

Its formula is Ca₂Al₃[O|OH|SiO₄|Si₂O₇].

It was originally discovered in 1896 in Tyrol, Austria

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

, and is so-named because of its resemblance to zoisite

Zoisite

Zoisite is a calcium aluminium hydroxy sorosilicate belonging to the epidote group of minerals. Its chemical formula is Ca2Al3O...

.

Forms a continuous solid solution series with substitution of Fe(|||) for Al(|||). Only the m3 site accepts Fe(III) readily.