Historically many different green, red and blue materials have been described as emeralds, rubies and sapphires. 

Here are a few examples;

Medina emerald which is green glass
Night emerald which is peridot
Oriental emerald which is green sapphire
Spanish emerald which is green glass

American ruby which is garnet
Australian ruby which is garnet
Balas ruby which is spinel
Siberian ruby which is tourmaline

Brazilian sapphire which is topaz or tourmaline
Spinel sapphire which is spinel
Water sapphire which is iolite

Conversely, Burmese rubies are from Burma (or Myanmar, although the trade still refer to the stones as Burmese) and because of their colour are acknowledged as one of the finest rubies, carrying a serious price premium. Just because rubies may be described as Burmese doesn’t necessarily mean they are though… this is why it is important to have trust in and a good relationship with your stone dealer or jeweller so that you can be confident in what you are buying.