If the Salagrama murthi at home is chipped or split into pieces, can we perform Tiruvaradhanam for that murthi? Or must we replace it with a new Salagrama? Kindly also explain how and where to procure Salagrama murthi.

It is mentioned in the scriptures that a few harms are associated when Tiruvaradhanam is performed for chipped or split Salagrama. So, one must replace the Salagrama. Until such time one can continue with the existing Salagrama.