Калцедон — разлика између измена

* [http://depts.washington.edu/uwch/silkroad/texts/weilue/weilue.html See Section 12 of the translation of ''Weilue'' - a 3rd century Chinese text by John Hill under "carnelian" and note 12.12 (17)] {{Wayback|url=http://depts.washington.edu/uwch/silkroad/texts/weilue/weilue.html |date=20050315032618 }}