On June 16th this year, the utsava or processional deities of Lord Venkateswara (also commonly called Balaji) of Tirupati were adorned with the vajra kavaca or adamantine armor on the first day of the Jyestabhisheka festivities. The processional deities, named Sri Malayappa Swami, along with His divine consorts Sri & Bhu Devis give devotees darshan wearing this jewel studded kavaca only once a year.
The following day the Lord gives darshan wearing muthyalu kavaca or pearl armor.
The third and final day of the festivities, the deities are adorned with the swarna kavaca or gold armor, which They wear for the rest of the year. The Jyestabhisheka festivities are observed for the protection of the utsava deities, and Their year-round maintenance.
For more information about the Jyestabhisheka festivities, check out: http://en.wikipedia.org/wiki/Abhideyaka_Abhishekam
Thanks to Sri Rameshbabu for the beautiful pictures of Lord Malayappa with His consorts. For more: