A crest is simply the representation of a three-dimensional object which is placed above the helm over the shield in a coat of arms.
Chiefs of Clans
Chiefs have the right to wear their Crests as badges either simpliciter, without the accompaniment of circlet, motto or feathers behind the badge, or, as is more usual, surrounded with a plain circlet inscribed with his Motto or Slogan, NOT a strap-and-buckle which is for clansmen; and, if they choose, with THREE eagle’s feathers in silver behind the circlet.
Heads of Families
Heads of large branches of a Clan, who have been Officially Recognised as Chiefs by the Lord Lyon King of Arms, may wear: either their own personal Crest within a plain circlet inscribed with the Motto, as for a Chief, but with two small eagles’ feathers instead of the Chief’s three. If the Head of Family is also a Peer, he may add the appropriate coronet of rank on top of the circlet, or they may wear their Chief’s Crest badge without feather like any other clansman, as described for clansmen, below.
A person who has registered his or her own coat of Arms and Crest, or inherited these according to the Laws of Arms in Scotland from an ancestor who had recorded them in the Lyon Register, may wear his/her own Crest as a badge: either on its Wreath, Crest Coronet or Chapeau,or, as is more usual, within a plain circlet inscribed with his Motto.An armiger may also choose to wear instead the Crest badge of his Chief if the armiger is a clansman. An armiger is entitled to one silver eagle’s feather behind the plain circlet, and if s/he is also a Peer s/he may add the appropriate coronet of rank on top of the circlet.
Clansmen and clanswomen
These are the Chief’s relatives, including his own immediate family and even his eldest son, and all members of the extended family called the “Clan”, whether bearing the Clan surname or that of one of its septs; that is all those who profess allegiance to that Chief and wish to demonstrate their association with the Clan.It is correct for these people to wear their Chief’s Crest encircled with a strap and buckle bearing their Chief’s Motto or Slogan. The strap and buckle is the sign of the clansman, and he demonstrates his membership of his Chief’s Clan by wearing his Chief’s Crest within it.
Crest of the Duke of Roxburgh Crest of the Earl of Roseberry