In order that every appearance of pantheism, naturalism or nihilism be avoided, it is not permitted to scatter the ashes of the faithful departed in the air, on land, at sea or in some other way, nor may they be preserved in mementos, pieces of jewelry or other objects. These courses of action cannot be legitimized by an appeal to the sanitary, social, or economic motives that may have occasioned the choice of cremation.
When the deceased notoriously has requested cremation and the scattering of their ashes for reasons contrary to the Christian faith, a Christian funeral must be denied to that person according to the norms of the law.
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The Full text of the Vatican Document on Cremation
In order that every appearance of pantheism, naturalism or nihilism be avoided, it is not permitted to scatter the ashes of the faithful departed in the air, on land, at sea or in some other way, nor may they be preserved in mementos, pieces of jewelry or other objects. These courses of action cannot be legitimized by an appeal to the sanitary, social, or economic motives that may have occasioned the choice of cremation.
When the deceased notoriously has requested cremation and the scattering of their ashes for reasons contrary to the Christian faith, a Christian funeral must be denied to that person according to the norms of the law.
Read it all.