Express Big Monday

[Steve Klein]

Last one and I cannot seem to reference it anywhere.

27 across: Dark, fine-grained volcanic rock consisting of plaglociase feldspar named after a South American mountain range

8 letters: - n - e - - t -

Many thanks in advance - there always seems to be someone clever enough to come up with the answer when I get stuck..
Steve (K)

[wallacia]

andesite.

[Steve Klein]

Thank you so much wallacia. Really appreciate your help

Steve

[wallacia]

you are welcome steve,i used this site to find the answer,just typed in the letters you had,i keep it in my favourites.

http://www.onelook.com/