The shell plays an important role in Tibetan Buddhism, Hinduism and Feng Shui (the latter being a genuine guideline on how to organise and equip the home or workplace harmoniously).
Please note: this is a natural product, variations in size and colour are normal, as are 'imperfections' around the edges and surface.

Feng Shui
The seashell plays an important role in Feng Shui, because it is believed to bring great benefits. It gives a sense of peace and comfort within the home as well as acting as protection. According to Feng Shui: placing a seashell in the south corner of the living room is said to enhance the popularity and reputation of the householder; placing smooth seashells in the kitchen is said to create harmonious, family-oriented energy; keeping pointed seashells on the window sill helps to attract energy that protects the house from bad luck and damage; keeping a basket full of seashells on a table near the front door helps to have a satisfying and successful career.
Tibetan Buddhism
The conch is commonly used to "summon religious assemblies". It is also used to hold 'holy water' and as a musical instrument in puje, ceremonies.
What is a puja?
Puja (literally offering) is a ritual meditation dedicated to a Buddha or Bodhisattva. It is a ceremony where prayers are offered to the Buddhas to ask for their blessings or invoke their help. A puja can be dedicated for meditative practice, for purification, for removing obstacles, for long life, in case of death, for an illness, for business and so on. Pujas are performed to avoid and eliminate the three types of obstacles, conditions that prevent us from achieving our worldly and spiritual goals.
India - Hinduism
The conch is used to chase away evil spirits and to prevent natural disasters. Some use it to "scare away poisonous creatures". And, as explained above, the conch is also used in pujas.