Kundalini Tantra takes the help of traditional symbology to make various references of the potential experience of the divine Shiva Linga, when a Sadhaka crosses one chakra after the other in their attempt to experience super consciousness. In the Mooladhara the Shiva Linga is represented as a Swayambhu Linga or Dhumra Linga, which is smoky grey in color. The Kundalini Shakti in three and a half coils around this Linga, her luster being as bright and piercing as that of lightening. Could this in reality be a representation of the Parada Linga which is grey in color and made of mercury? Does the worship of the Parada Linga in specific help cross the hurdle of the Mooladhara and cleanse the mind of its instinctive ignorance?
The existence of the Kundalini echoes in almost all temples across India. The three and half serpent coil is what is most often seen within the Garbha Griha of the main shrine, bringing the whole vision of the supreme into these houses of stone that represent our womb, the location where this chakra originates. Does it take divine light and consciousness represented by the brightness of fire to have a glimpse of this reality through the art of arti performed at the shrine?
At the Ajna Chakra the supreme consciousness is represented as a black Linga. This is called the Itarakhya Linga. In this state of consciousness the representation of awareness is a more pronounced version of "What I am". Most Shiva temples represent the form of the Linga in black granite. Were the ancients trying to remind us of our original goal having taken birth in this universe by echoing it across monuments of stone systematically across the land, the root purpose of our life being the realization of Who I Am?
The experience at the Anahata Chakra is that of the inverted triangle of Shakti in burning Akhanda Jyoti, the unflickering eternal flame which is essentially the awareness of the jivatma. In the Tantrik texts this Linga is represented as the Bana Linga. It is believed that the Banalingas in reality are the essence of Shiva and do not require any pranapratishta for their worship. These are superior Linga stones are not are easy to procure.
The Bindu Visarga brings with it the cool experience of the moonlit night with the crescent moon shining in the night sky. The crescent moon represents the drop of ambrosia acquired which elevates the Sadhaka's state to that where material sustenance ceases to exist, they completely disconnect from our world. At this point the cosmic sound of OM is heard within the being of the Sadhaka.
Last and by far the most supreme, is that of the luminous Linga experienced at the Sahasrara Chakra. This is represented by the Jyothir Linga which is formless. This is the state of the void, the nothingness where the Sadhaka ceases to exist in relation to "I". Could this in reality be represented by the Spatika Linga which is transparent, and yet almost invisible?
It amazes me that each Linga experienced in the spiritual journey has possibly been represented in material form through natural stones/metals available in nature. How far deep does this search go, how far beyond is the truth and how much closer can it be if its within me to realize?