Nepheline Thin Section

Basal section of nepheline in a foidite from cape verde.

Nepheline thin section. Nepheline has very low relief and is colourless in ppl. 19 ruff info 20 ucla petrography thin sections 21 www mincryst. Xpl image 10x field of view 2mm nepheline crystals in a foidite from cape verde.

Nepheline is a very unremarkable mineral and therefore easy to overlook. This hexagonal crystal is oriented with its optic axis vertical. Photomicrograph of nepheline sample k 21 under plane polarized light.

This is a thin section of a nepheline syenite from an unknown source but probably kola. Search for nepheline using. As stout six or twelve sided prisms terminated by dominant f0001g typically poorly formed to 10 cm.

General nepheline information. They can also be colorless gray yellow or red brown. Ppl image 10x field of view 2mm nepheline crystals in a foidite from cape verde.

Nepheline is colorless under plane polarized light in thin section. Xpl image 2x field of view 7mm nepheline crystals in a foidite from cape verde. Click on the image to see the crystal under crossed polars.

In thin section this rock contains orthoclase feldspar laths which exhibit simple twinning slightly higher relief and dusty grains of nepheline phlogopite mica which is pleochroic in dark brown to straw yellow and rare melanite garnet. Under xpl it shows 1st order greys is untwinned and has very little to distinguish it from untwinned k feldspar. Reddish brown to black triclinic aenigmatite occurs also in these rocks.