You have perfect new micro sd card properly formatted with fat32 filesystem and you receiving unable to mount of find sd card error when you try to access files on your phone if thats the case theres simple fix for that , there isnt any hardware or software error , your new memory card just needs to proper partition itself. to solve this issue follow these steps :
1.turn off your cell phone
2. pull out the sd card and connect this card to your computer.
3.install this free software to create partition .
4.once downloaded and installed run the installed program make sure card is connected to your pc
5.select the micro sd drive and click new partition make sure settings are : type = FAT32 and it should be set to “Primary” after this apply the changes 6.once changes are applied properly eject the sd card from your computer .
7.insert the card back to phone 8.hold down the volume down key and power button until you see the flash screen on phone .
Congrats your card is fixed properly
, any issues ? comment below and i will try my level best to reply asap