To prevent chipping of the pointed ends of a marquise diamond:
Ensure the diamond is set with protective prongs, especially V-shaped ones at the tips.
Consider a bezel setting or a halo setting that surrounds the diamond with a ring of smaller stones for additional protection.
Be mindful of the ring during daily wear, and remove it during activities that may expose it to hard knocks or pressure.
Regularly inspect the ring to make sure the prongs remain secure and intact, as weakened prongs can increase the risk of damage.
Proper care and setting choice are crucial in protecting a marquise diamond's delicate points.