Colour, characteristics:

Colour light to dark grey, greenish grey, some varieties also black-grey.

- Light-coloured minerals: 50-85%

Of which:

Feldspar: 80-100%
Of which:

-alkali feldspar: 0-35%

-Plagioclase feldspar: 65-100%

Quartz 0-20% or Foide 0-10%

- Dark minerals: 20-65%

- Minor minerals:

Pyroxenes, hornblende, olivine, biotite, magnetite, ilmenite, pyrrhotite

Structure of the diorite small- to medium-grained. The minerals are usually mixed together without any recognisable direction. Diorite is compact, without perceptible cavities, very resistant to weathering. A rare variety of diorite is spheroidal diorite. Here, spherical, single- or multi-shell formations are embedded in a medium to fine-grained matrix.

Formation:

By very slow cooling of molten rock in the depths of the earth's crust. Occurs at the edge of large granitic rock bodies, in small stocks or veins, not very common. Formation of spheroidal diorite through rhythmic crystallisation.

Places of discovery:

Bavarian Forest, Harz Mountains, Odenwald, Black Forest, Finland, Scotland

Products: