Is there any difference between white egg shells and brown egg shells?

Science Fair Project Information
Subject: Chemistry
Grade level: Elementary School - Grades 4-6
Academic Level: Ordinary
Project Type: Experimental
Cost: Low
Awards: None
Affiliation: Canada Wide Virtual Science Fair (VSF)
Year: 2004
Description: White egg shells and brown egg shells were compared in the following parameters: membrane permeability and physical strength.
Link: http://www.virtualsciencefair.org/2004/gawn4e0/public_html/