Vishuddhi
From Sahaja Yoga Encyclopedia

The Vishuddhi is the chakra or energy centre in the vicinity of the neck and shoulders.
The Vishuddhi chakra ... connects you to the Virat, to the whole. So you come to the point where you know that it is the true Vishuddhi chakra. You know the whole akbar. You get connected with Him. The rapport is established through the Vishuddhi chakra and you can feel it. It is communicated. (Shri Mataji Nirmala Devi 2 February 1983)
Petals: sixteen
Element: ether
Planet: Saturn
Weekday: Saturday
Gemstone: sapphire
Some of the qualities of the Vishuddhi are collectivity and communication.