I have some contacts in Gmail chat that I don't know its email. And in some other I have the option to send them an email, why is that? Is there a way to see the contact email?
Contact with email:
Contact without email:
Gmail – How to know email of a Gmail chat contact
gmailgoogle-contacts
Related Solutions
While Lipis' answer still works, there's another method as well.
With the message open, hover your mouse pointer over the sender's name. An info card will pop up. If the address is not already in your contacts, you can click the "Add to Contacts" button to open a contact edit form with the name and email address already filled out.
(The Add and invite button is for adding the person to your Google+ Circles.)
Make sure you deleted it from all contacts, meaning from Other contacts as well. Also, in the chat list, you should have chosen Block, not Never show.
When you search for it and you find it, the very first item in that list is the box with his/her details (i.e. “it still throws up the contact's email address with options to "start a video chat", "chat" etc.”), right? There, next to the name you should have a small down-arrow — click on it and choose Edit contact details (see images below). This should send you to the contact’s details page where you can delete it from the More button in the menu.
Best Answer
There are several factors at play here:
No One(assuming you are in their Circles as well).