- http://www.fieldgemology.org/gemology%20tanzania%20ruby%20sapphire%20spinel%20tsavorite%20alexandrite%20emerald%20tunduru%20songea%20morogoro%20merelani.php
- http://www.fieldgemology.org/Tsavorite_article.php
- http://www.ruby-sapphire.com/tsavorite-untamed-beauty.htm
- http://www.fieldgemology.org/Spinel_article.php