Unlike with diamonds, most Gemstones give away their origin by their chemical signature and types of impurities. Location can have a significant impact on value, some locations are more highly sought after than others, even comparing similar looking stones.
The premium source of Rubies is Burma (Myanmar) due to the heritage and scarcity. 2nd in line is Mozambique and Thailand, followed by Tanzania and Madagascar and finally Vietnam.
The premium source of Sapphires is from Kashmir, followed by Burma (Myanmar). Sri Lanka is the third finest, with Madagascar and Tanzania as the fourth. The final sources are from Basaltic origins (Australia, Ethiopia, Nigeria, Vietnam, Thailand and Cambodia).