The light of consciousness manifesting out of Sadaashiv is, in reality, the Shiv Ling. From Him all the moving and unmoving creations take their origin. He is the Ling or cause of everything. In Him, the whole world merges itself finally. The Shiv Puraan says: “Peetham Ambamayam Sarvam ShivaLingasch Chinmayam.” The support or Peeth of all is Prakriti or Paarvatee, and Ling is the Chinmaya Purush, the effulgent light which is self-luminous. Union of Prakriti or Paarvatee, and Purush or Shiv Ling is the cause of the world. In Sanat Kumaar Sanhitaa of the Shiv Puraan, Shiv says: “O Paarvatee, the daughter of mountain, there is none dearer to Me than the man who worships Me in the Ling, knowing that Ling is the root cause of everything and knowing the world to be Ling-maya or Chaitanya-maya.”

The Ling is like an egg. It represents the Brahmaand (cosmic egg). Whatever that is contained in the Brahmaand is cntained in the Ling too. The whole world is the form of Shiv. The world is a Ling. Ling also is the form of Lord Shiv.

Ling signifies that the creation is effected by the union of Prakriti and Purush. It means Laya, Gyaan, Vyaapya, Prakaash, Arth Prakaash, Saamarthya and the symbol which denotes the above meaning. Ling means the place of dissolution for the world and all beings. It signifies also Satya, Gyaan and Anant -Truth, Knowledge and Infinity. It indicates that Lord Shiv is endowed with all-pervading and self-luminous nature. Ling is a symbol which makes us understand the various kinds of Arth which are indicated above. There are six types of Ling, viz., And Ling, Pind Ling, Sadaashiv Ling, Aatm Ling, Gyaan Ling and Shiv Ling. All these Ling are taken to mean the characteristics by which the And (the Universe), Pind (the body), Sadaashiv, etc are to be recognized and understood.

The union of the Ling with Yoni is a representation of the Eternal Union between the static and the dynamic aspects of the Absolute Reality. This represents the Eternal Spiritual Communion of the paternal and the maternal principles from which all the phenomenal diversities have originated. This is an eternal communion of the Changeless Being and the Dynamic Power or Shakti from which all changes flow.

Further, the lower sexual propensities in the aspirants are eradicated by this sublime conception. The spiritualization and divinization of the Ling and Yoni, helps the aspirants to free themselves from sexual thoughts. All base thoughts gradually vanish by entertaining this lofty idea. All sexual relations in this world are spiritualized as the manifestations of the ultimate Creative Principle, of the eternal Self-enjoyment and Self-multiplication of Lord Shiv in and through His Power or Shakti. The union of the Ling with Yoni symbolizes the creation of this universe by Lord Shiv in conjunction with His Shakti or Power.

The so-called educated men of the modern age have not attained enough spiritual insight and philosophical penetration that they can understand its spiritual meaning, hence, they criticize the union of Ling with Yoni as immoral and obscene, owing to their extreme ignorance and lack of enquiry, deep thinking and Satsang or association with sages. Although this is highly deplorable and lamentable, but there are many who are like them. May Lord grant wisdom to these poor ignorant souls!

Types of Ling

Ling are of two types - Kritrim (man-made) and A-Kritrim (natural). A-Kritrim Ling include Swaayambhoo and Baan Ling.

There is another classification of Ling - Chal (movable) and A-Chal (immovable). Chal Ling are made of metals, clay stones and wood and are normally worshiped at homes. Rubies, pearls, corals, topaz, emerald and diamond are the precious stones are also used for Chal Ling. Gold, silver, copper and bell metal are the metals used for Chal Ling. A-Chal Ling made of stone are usually fixed in temples with a pedestal and the Ling proper.

Different materials are recommended for fulfillment of different kinds of desires to make the Ling. For example - topaz Linga gives prosperity; pearl Ling removes sins etc. The Sphatik Ling is considered sacred and is believed to yield
immense benefits to the worshipers. It is this type which is generally used for rudraabhisheka at homes.
 

It is important to know that the Ling are divided into three parts -
The lowest part, called Brahmaa Bhaag is square in shape.
The middle part represents the Vishnu Bhaag and it is octagonal in shape.
The top most part, the cylinderical part of the Ling.  is the Rudra Bhaag and it is this portion which is worshipped (Poojaa Bhaag).

Stories of Dadheechi, Vyaas, Nandee, Soorya Vansh and Chandra Vansh kings, Kaashee etc are the other stories.
Shiv's eight forms, Shiv's Panchaaksharee Mantra and the meditation of Shiv after establishing Shiv Ling, the Mrityunjaya Mantra are the other contents.

Shiv's idol is depicted in different forms Roop) - Saumya or Anugraha Moorti; Ugra; Raudra; Sanhaar Moorti; Nritya (dance pose) or Taandav Nritya.

Sphatik Ling
God is Nir-Aakaar and Nir-gun. No particular form or specific qualities are assigned to Him. A uniformly rounded surface has been conceived as the best representation of such a God. Ling also represents Devee, Ganapati and Narasinh in addition to Shiv and Rudra.

Worshipping Ling

The sculptured image of Shiv and Paarvatee worshiping a Ling in the Kailaash Naath temple in Ellora adds to the mystery that the Ling may be a very ancient object of reverence.

Shiv is said to have manifested himself as a great altar of gold from which sprang forth a blazing fire before Ashwatthaamaa.
This is as mentioned in the Mahaabhaarat (Sauptikaa Parv). Certain non-Vaidik cults wherein phallic worship might have existed as in many ancient civilizations of the world might have been absorbed into the Vaidik culture and the same has been elevated to the father-mother principle at the cosmic level. We may also remember that the Ling have been described as emblems of the Devee, Ganapati and Narasinh and are worshipped as such.

The Ling Puraan states that when Vishnu and Brahmaa were puffed with arrogance ignoring Shiv, he appeared before them as a pillar of fire of infinite length whose extremities could not be found. This pillar of fire came to be known as Ling because all creatures merge in it at the time of destruction (leeyate asmin, layam gachchanti). Read this story here.

Ling in Kaashee

There are 511 Shiv Ling in Kaashee. Out of these the 12 Swaayambhuva Shiv Ling are:-
1. Avimukteshwar,
2. Omkaareshwar,
3. Jyeshtheshwar,
4. Madhyameshwar,
5. Aadi Mahaadev,
6. Vishweshwar,
7. Vrishabh Deveshwar,
8. Kedaareshwar,
9. Kapardeeshwar,
10. Swaayambhuva Lingeshwar,
11. Bhoorbhuveshwar,
12. Veereshwar,

In addition to these, there are several others installed by deities, Rishi and Graha (planets) and Shiv Gan.