from ursula's site: several known lover's knot tiaras, including pictures of Queen Mary in her tiara with and without the pearl spikes on top.
Loversknots Tiara |Das "Liebesknoten" Perlen Diadem
In the row above Queen Mary are pictures of the original Cambridge lover's knot tiara, that inspired Queen Mary. (I don't know it's name) The woman on the far left is her Grandmother, the Duchess of Cambridge, and the second shows her aunt, Grand Duchess Augusta of Mecklenburg-Strelitz.