The identifier is what is used to create the unique* avatar deterministically (so the same user will always get the same avatar). With the exception of the gravatar mode, the order of precedince is: 1. name, 2. username, 3. email, 4. hash. so with that in mind, if you wanted the avatar to be generated from, lets say, the users email you must not supply a name or username prop. Gravatar works a little differently by trying the hash first, then hashing the email and trying that.
Prop
Type
Default
Description
name
String
Sets the users name
username
String
Sets the users username
email
String
Sets the users email
hash
String
Sets the avatar hash
Options
Common Options to all modes
Prop
Type
Default
Description
mode
String
initials
must be one of [ initials, robohash, adorable, gravatar ]
size
Number
128
Size of the image to be loaded
alt
String
alt tag to be applied to the image. falls back to the used identifier