English to French Other Mining & Minerals / Gems

Hi all,

Documentation about pink gemstones...

"Although the origin of this pinkish colouration is still a matter of debate, scientists generally agree that it is caused by tiny abrasions within the diamond at the microscopic level and not by the presence of any elements from the periodic table.

This effect, known as graining, causes the total absorption of all colours, except for pink, from the visible spectrum, giving the stone its pink colour."

I found "ligne de croissance" ou "ligne de cristallisation" in Termium Plus: http://www.btb.termiumplus.gc.ca/tpv2alpha/alpha-fra.html?la...

but I want to make sure we don't use the word "grainage" here...

Thank you for your help