In many old shiva temples we can find Lingams with some markings on it. The markings aren't same in every lingam. Are those markings is to identify that the lingam is consecrated for a particular chakra? Is there a way to find which chakra a particular lingam has been consecrated?
TO HAVE A DEEPER INSIGHT INTO SECRET OF LINGA PLEASE REFFER TO---- KHECHARI KRIYA---BIOLOGY. Khecheri kriya is to stimulate UVULA (LINGA or PSEUDO PHALLUS or object that resemble a small mini hanging penis) by the TIP OF tongue. Actually in Samadhi one need not do it forcefully rather it shall HAPPEN SPONTANEOUSLY when the tongue clings to the hard palate and abuts UVULA rubbing it to produce MADHU or nector or AMBROSIA.
SEE MADHU IN NATH PARAMPRA POTHI.
My answer will concentrate on the appearance of the lingas present in the chakras in the Kundalini Yoga. (Though there is not much).
- Swayambhu Lingam in Mooladhara Chakra.
Inside it (the triangle/yoni) is Svayaṃbhu in His Linga-form, beautiful like molten gold, with His head downwards. He is revealed by Knowledge and Meditation, and is of the shape and colour of a new leaf. As the cool rays of lightning and of the full moon charm, so does His beauty. The Deva who resides happily here as in Kāśī is in forms like a whirlpool (have vacuum/depression on the top of the Linga).
Over it shines the sleeping Kuṇḍalinī, fine as the fibre of the lotus-stalk. She is the world-bewilderer, gently covering the mouth of Brahmadvāra/Brahmarandhära by Her own. Like the spiral of the conch-shell, Her shining snake-like form goes three and a half times round Śiva.
By meditating thus on it who shines within the Mūla-Cakra, with the lustre of ten million Suns, a man becomes Lord of speech and King among men, and an Adept in all kinds of learning. He becomes ever free from all diseases, and his inmost Spirit becomes full of great gladness. Pure of disposition by his deep and musical words, he serves the foremost of the Devas.
- Bana Linga in Anahata Chakra.:
The Śakti whose tender body is like ten million flashes of lightning is in the pericarp of this (Anāhata) Lotus in the form of a triangle (Trikoṇa). Inside the triangle is the Śiva-Linga known by the name of Bāṇa. This Linga is like shining gold, and on his head is an orifice (bindu) minute as that in a gem. He is the resplendent abode of Lakṣmī (Beauty/Sri).
He who meditates on this Heart Lotus becomes (like) the Lord of Speech, and (like) Īśvara he is able to protect and destroy the worlds. This Lotus, is like the celestial wishing-tree, the abode and seat of Śarva. It is beautified by the Haṃsa, which is like unto the steady tapering flame of a lamp in a windless place. The filaments which surround and adorn its pericarp, illumined by the solar region, charm.
- Itara Linga in Ajna Chakra.:
Within this Lotus dwells the subtle mind (Manas). It is well-known. Inside the Yoni in the pericarp (of Ājñā Chakra) is the Śiva called Itara, in His phallic form. He here shines like a chain of lightning flashes. The first Bīja of the Vedas, which is the abode of the most excellent Śakti and which by its lustre makes visible the Brahma-sūtra, is also there. The Sādhaka with steady mind should meditate upon these according to the order (prescribed).
The excellent Sādhaka, whose Ātmā is nothing but a meditation on this Lotus, is able quickly to enter another’s body at will, and becomes the most excellent among Munīs, and all-knowing and all-seeing. He becomes the benefactor of all, and versed in all the Śāstras. He realises his unity with the Brahman and acquires excellent and unknown powers. Full of fame and long-lived, he ever becomes the Creator Destroyer, and Preserver, of the three worlds.
I hope this helps. Prd..