Traits
The chakra-mark is the most distinguishing feature of the Dvaravati stones, and hence they are called "chakrankita-sila". According to Garuda Purana, there are twelve varieties of this stone, owing to the number of chakras (wheels), colours and forms (Sanskrit sloka in this regard states:‘dasadha cha prabhinnas ta varnakrti-vibhedatah’). When there is only one chakra, the stone is called Devesa; when there are two chakras, it is Sudarshana; three chakras represent the deity Ananta. When there are four chakras, the stone is Janardana. Vasudeva is represented by the stone having five chakras, Pradyumna by six chakras, Bala-bhadra by seven, Purushottama by eight, Nava-vyuha by nine, Dasavatara by ten, Aniruddha by eleven and Dvadastma by twelve. Nava-vyuha represents the collection of nine forms of Vishnu: Vasudeva, Samkarshana, Pradyumna, Aniruddha, Narayana, Hayagriva, Vishnu, Nrsimha and Varaha. The first four forms are well known as ‘chatur-vyuha’. The twelve major forms of Vishnu are derived from these nine forms, according to the Tantra siddhanta, a division of Pancharatra.
Prahlada Samhita, quoted in Salagrama-pariksha (by Anupasimha) gives the first few names differently. The Dvaravati Sila with only one chakra is called Sudarsana, with two chakras 'Lakshmi-narayana' and with three chkras[check spelling] 'Trivikrama'. The rest of the names are the same as given above. The name Ananta is given to stones which have more than twelve chakras. The name for Dasavatara in the above list is given here as 'Dasamurti'. When the chakras are more than twelve, only even numbered chakras are to be preferred, according to Galava-smrtir.
Benefits
These Silas also have distinct personalities like the Saligrama Sila that are identified by their size, colure, texture markings; these are explained below.
I.Sudarshana: one chakra - salvation
II.Lakshmi-Narayana: two chakras- salvation
III.Trivikrama: three chakras - freedom from the fear of births and deaths
IV.Janardana: four chakras - fulfillment of desires
V.Vasudeva: five chakras - obtainment of prosperity and elimination of enemies
VI.Pradyumna: six chakras - wealth and lustre
VII.Baladeva: seven chakras - continuation of progeny and celebrity
VIII.Purushottama: eight chakras - satisfaction of all that one aspires for
IX.Navavyuha (the collection of nine forms of Vishnu): nine chakras - rewards, which are difficult, even for the gods to obtain
X.Dashmurti (the ten incarnations of Vishnu): ten chakras - sovereignty and prosperity
XI.Aniruddha: eleven chakras - lordship
XII.Dvadasatmaka: twelve chakras - final emancipation
XIII.Ananta: more than twelve chakras - fulfills one’s desires (only even numbered chakras are to be preferred)
The colour and the shape of the sila is said to give following effects.
Ø White stones are considered most suitable for worship and will make for a worldly prosperity in all aspects and spiritual welfare
Ø Dark (blue-black) stones forebode death
Ø Tawny ones cause anxiety
Ø Multi-coloured ones bring about disease and sorrow Ø Yellow ones take away wealth
Ø Smoke coloured ones produce loss of wealth
Ø Blue stones will bring about obstacles to any undertaking
Ø Round in shape or square auspicious
Ø Triangular or uneven in shape inauspicious