GeoClick: reading the Michel Levy Color chart

Students should be familiar with using the chart and

Students should be able to apply the chart to determine birefringence

Students should understand how thickness and birefringence produce specific interference colors.

Appropriate for Mineralogy or Petrology undergraduate students, after they have learned about birefringence, interference colors, and have been introduces to the Michel-Levy chart

Prompts:

Scaffolding / Orientation: 

1. Click on the chart where the band of color for 2nd order red intersects with a 30 micron thickness.

2. If you have a standard 30 micron thick thin section and your mineral shows 2nd order red colors (from question 1), click where you would read the birefringence for that color and thickness.

Prediction/Process: 

3. If a mineral of standard thickness (30 microns) has 2nd order red interference colors (box in red), what interference colors would you expect when it is ground down to 20 microns thick?

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The Michel-Levy interference color chart.

Provenance: ZEISS Microscopy from Germany
Reuse: This item is offered under a Creative Commons Attribution-NonCommercial-ShareAlike license http://creativecommons.org/licenses/by-nc-sa/3.0/ You may reuse this item for non-commercial purposes as long as you provide attribution and offer any derivative works under a similar license.

I suggest having students discuss their answers between each question.