They are Unicode , but Unicode is used to encode and decode what a set of bits is representing , it isn ' t for storing visual information about a character . Like with Unicode 8 , there are 8 bits used to reference a character such as the letter ' t '. Those 8 bits aren ' t nearly enough information to store the information needed to visually draw the letter ' t '. It ' s the same with emoticons Unicode supports a specific set of emoticons dog , American flag , winky face , etc but it doesn ' t tell you how to render them just what they are . If they did store what the character looked like , not only would each character take up a ridiculous amount of storage space , but it would be harder to have different fonts . It ' s up to whoever is decoding the characters to have some data on how to render them . This results in platforms having varying renderings for the emoticons just like the characters . Most of these platforms like to have their own emoticons because it allows them to fit their visual appearance with that of the platform . So Apple has a different approach visually and thematically to their platform than Google does .