FORM - 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10 and Rule 13) A PARTICULATE FLUORESCER AND A PROCESS FOR PREPARING THE SAME HINDUSTAN UNILEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India The following specification particularly describes the invention and the manner in which it is to be performed. Field of the Invention This invention relates to a bipolar particulate fluorescer for use in laundry detergent compositions, fabric conditioners and personal care compositions and a process for making the same. Background of the invention Optical enhancers/brighteners are used widely in many technological fields like detergents and personal care, especially in laundry (wash and fabric conditioning) and in personal care compositions (e.g. skin lightening and sunscreen compositions) for giving a consumer desired optical effect to the substrates. Modern day consumers prefer a detergent product that looks white. Consumers also prefer that fabric articles, washed with a detergent product, look bright. Similarly there is a desire of consumers in many parts of the world to change the appearance of their skin, either by skin tanning or by skin brightening. To accommodate those consumer preferences, it is a common practice to add fluorescer molecules in detergent compositions to make a detergent powder look white and attractive in appearance and to provide a brightening benefit to fabric articles washed with this powder. Fluorescers are also known as optical brighteners. These molecules generally absorb amongst other invisible light such as ultraviolet light, and emit this energy in another form. For the purpose of detergent products, the light is generally emitted in the visible spectrum, preferably blue or green light. The extra emission in the blue and/or green range of the spectrum makes fabrics or textiles washed with detergent comprising fluorescer molecules look brighter after washing. Fluorescer molecules get adsorbed in or otherwise attached to the fabric and give the desired effect. There are many detergent powders available in the market comprising various fluorescer molecules. The drawback of the currently available fluorescer molecules is that high amounts of fluorescer get lost during the rinsing stages of fabric washing processes. Therefore washed fabrics end up with a very low amount of adsorbed fluorescer which is not sufficient to produce the desired effect. Therefore the dosage of fluorescer in washing products has to be higher than required to compensate for the loss. Since fluorescers are relatively expensive ingredients it is desired to reduce the loss on rinsing. Another problem of known fluorescers is that they are generally fabric specific. Some fluorescers work well on e.g. cotton, but not on polyester and vice versa. The use of carrier material for better fluorescer deposition on to fabric is also disclosed in literature. US2007/0203052 discloses a particulate fluorescer (brightener), wherein the carrier is urea formaldehyde, in order to deposit particulate brightener on to consumer articles during the wash. WO00/58431 (Ciba) discloses the use of a brightener pigment comprising a cellulose powder which is dispersible in water and a water soluble fluorescent whitening agent for increasing the whiteness of cleansers or detergents. DE 195 38 039 discloses a detergent in agglomerate form characterized in that it contains at least one swellable layer silicate and at least one optical brightener in intimate contact with each other. DE 195 38 039 use swellable clay which are not anisotropic in terms of their surface characteristics. US 5,449,402 discloses a functionally modified pigment particle is prepared by mixing a flocculated pigment of kaoline clay or calcium carbonate with a modifier having charge sites opposite in sign to the charge sites of the flocculated pigment. In US 5,449,402 the flocculated kaoline clay is first binded with a latex binder and then treated with modifier. This particle thus does not show anisotropic behaviour with respect to their surface property and thus not suitable for the present purpose. All these documents do not provide a teaching for making a fluorescer with low fabric specificity and with improved retention on the fabric so that higher amount of fluorescer will stick to the fabric even after rinsing. This remains to be desired. Furthermore in today's polluting world and outdoor lifestyle most consumers want to protect and improve appearance of their skin and hair. That makes personal appearance/protection sector very important for consumer goods companies. Consumers from different parts of the world have different colour characteristics of their skin. This is attributed to their genetic structure and geographical conditions. Some consumers want to lighten their skin, whereas other consumers want to get tanned. Consumers also want to protect their skin, hair and scalp from harmful UV rays while exposing themselves to sunlight. There are several ways by which consumers may obtain protection from UV rays and also at the same time may improve their skin appearance. Skin lighteners are known in the art and serve a useful purpose in the repertoire of cosmetics. Skin lightening agents are generally biochemically active molecules which help to modulate the melanin synthesis. Photoprotection of skin from sunlight especially from UV rays is also known in the art. Sunscreens/sunblocks are generally used for this purpose. Sunscreens are generally organic molecules that absorb the UV light and emit the energy in a different form, for instance in the visible range of the spectrum or in the form of heat, thereby protecting the skin against sunburn. Similarly sunblocks help to protect the skin against possible sunburn. These sunblocks generally comprise inorganic particulates (like ZnO, TiO2) that reflect the incident rays in uv-visible region thus protecting the skin. Formulations using these molecules in the form of a cream, a lotion, gel, or spray are known. Many consumers believe that the currently available sunscreens or skin lightening agents in cosmetics may penetrate inside the skin which is not desirable. Another problem associated with currently available sunscreens in cosmetics is that there are usually many other ingredients apart from sunscreens, with which they may interact thereby reducing their stability. Objects: In view of the foregoing, it is an object of the present invention to provide a fluorescer with improved retention to the fabric so that larger amounts of fluorescer will be available even after rinsing. It is therefore a further object of the present invention to provide a fluorescer with low fabric specificaly. It is yet a further object of the invention to provide improved whiteness/brightness to fabrics and textiles. It is yet a further object of the invention to provide a fluorescer with improved stability when formulated in personal care compositions. It is yet a further object of the invention to provide improved skin appearance. It is still a further object of the invention to provide photoprotection of skin. Surprisingly it has been found that fluorescer molecules tagged by surface reaction onto naturally occurring asymmetric clay surfaces, act as a fluorescer particle with improved retention properties, low fabric specificity, higher stability in cosmetic formulations and/or yielding improved brightness and/or UV absorptions to substrate (skin/fabric) on use and meets at least one of the above mentioned objects. Summary of the invention 1 Accordingly the present invention provides a bipolar topospecific particulate fluoresces which precursor is an asymmetric 1:1 or 2:1:1 clay particle comprising alternating tetrahedral and octahedral sheets terminating with a tetrahedral sheet at one externa! surface plane and an octahedral sheet at another external surface plane, with fluorescer molecules having excitation wavelength between 200-500 nm selectively attached to the coordinating cations on one of the said external surface planes wherein said particulate fluorescer has anisotropic characteristics. In another aspect, the invention provides a detergent composition comprising particulate fluorescer of the invention. In another aspect the invention provides the use of the particles according to the invention for increasing whiteness of fabrics and textiles. In another aspect the invention provides a process of preparation of bipolar particulate fluorescer which precursor is an asymmetric 1:1 or 2:1:1 clay particle comprising alternating tetrahedral and octahedral sheets terminating with a tetrahedral sheet at one external surface plane and an octahedral sheet at another external surface plane, comprising the steps of (a) contacting the precursor with a mineral acid (b) adding a fluorescer molecule to the mixture (c) adjusting the pH to a range of between 2 and 10 and (d) heating the solution mixture at a temperature 50-150 °C and (e) separating the solid product comprising bipolar particulate fluorescer. In another aspect the invention provides a process for preparation of coated particle comprising the steps of (a) taking the solid bipolar fluorescer particle (b) adding it to a solvent containing the coating material at a temperature of 0°C to 100°C (c) stirring it for 10 minutes to 4 hours, (d) separating the coated particle, and (e) drying it at a temperature of 25°C to 55°C. In another aspect the invention provides a cosmetic composition comprising particulate fluorescer of the invention and a cosmetically acceptable base. In another aspect the invention provides the use of particulate fluorescer for improving skin appearance. In another aspect the invention provides the use of particulate fluorescer for photoprotection of skin. Fluorescer molecules according to the present invention are defined as the group of molecules having an excitation wavelength between 200-500 nm, wherein at least some electrons in the fluorescer molecule are brought from ground state to exited state induced by absorption of energy at the excitation wavelength. These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated. Detailed description of the invention Precursor The precursor of the particle with bipolar topospecific characteristics according to the present invention is an asymmetric 1:1 or 2:1:1 clay particle having alternating tetrahedral and an octahedral sheets terminating with a tetrahedral and an octahedral sheet at exterior surface planes. Particle of 1:1 clay is particularly preferred as precursor. According to the present invention preferred 1:1 clays include kaolinite and serpentine subgroups of minerals. The species included within the kaolinite subgroup include, but are not limited to, kaolinite, dickite, halloysite and naorite. The species within the serpentine subgroup include, put are not limited to chrysolite, lizardite, and amesite. According to the present invention preferred 2:1:1 days include chlorite group of minerals. Chloride is sometimes wrongly referred to as 2.2 day by some mineralogists. The chlorite comprises tetrahedral-octahedral-tetrahedral sheets like 2:1 clays, with an extra weakly bound brucite like layer between tetrahedral layers. The tetrahedral sheet preferably comprises coordinating tetrahedral cations of silicon. The tetrahedral sheet may also comprise isomorphously substituted coordinating tetrahedral cations which are not silicon. Isomorphously substituted coordinating tetrahedral cations include, but are not limited to, cations of aluminium, iron or boron. The octahedral sheet preferably comprises coordinating octahedral cation of aluminum. The octahedral sheet may also comprise isomorphously substituted coordinating octahedral cations which are not aluminium. Isomorphously substituted coordinating octahedral cations include cations of magnesium or iron. It is preferred that the fluorescer molecule is attached to the coordinating cations on the exterior side of one of the external surface planes- Accordingly, the fluorescer molecule is attached to coordinating cations on the exterior side of the tetrahedral sheet. Alternatively, the fluorescer molecule is attached to the coordinating cations on the exterior side of the octahedral sheet. According td a further aspect, coordinating cations on the exterior side of each of the tetrahedral and the octahedral surface sheets are attached to a fluorescer molecule, with the proviso that the fluorescer molecule attached to the coordinating cations on the exterior side of the tetrahedral surface sheet is not identical to the molecule attached to the coordinating cations on the exterior side of the octahedral surface sheet. The fluorescer molecule is preferably attached to the coordinating cations on the external surface of the octahedral surface plane and is not preferably attached to coordination cations of non-exterior tetrahedral or octahedral plane or on the interior side of the surface sheets. To provide a brightening effect on detergent powder, fabrics or skin, excitation of ultra violet