Coins are only used in Azar Web(the PC version of Azar) and Gems are only used in the mobile version of Azar.
Please be advised that :
1. Gems and Coins can be used in Azar Web
2. Gems cannot be purchased in Azar Web
3. Coins cannot be used in the mobile version of Azar
4. If you have Gems, they will be spent after Coins