Distinctive features:  
Generally coarse, green (reddish when weathered) pyroxene in which are set red garnets.

Colour: 
Pistachio green when fresh, but mottled with red when weathered.

Texture and granularity: 
Granular -- coarse to medium-grained.

Composition: 
Omphacite (green pyroxene), green hornblende and pyrope-almandine garnet. Kyanite and diamond sometimes occur.

Field associations: 
Metamorhposed gabbro, or basic magma crystallised at high pressure at grest depth.

Varieties:
Coarse and medium-grained varieties only.

 

As blocks in "blue ground" that fills diamone pipes in Kimberley, South africa, Norway, Scotland, USA, Asia.

 

Scientific.