Said by whom?

It makes a nice folk tale. However, in real life, snakes or boa in parts do not do this, regardless of their size. If that were so.. would you see so many snakes around you.. with their heads intact….?

It is impracticable for a Snake to have something hard like a diamond in its head/mouth. The fairy-tale status attached by Indians and all other cultures is perhaps to blamed for such beliefs & myth. Snakes are born from egg whereas diamonds are deep underground for several years.

Different cultures have variations of this story for a specific end. And is handed down as oral histories. The Greek wrote some stories in their scrolls.

1-In Wales, whenever a snake is found under or near a hazel tree on which the mistletoe grows, the creature has a precious stone in its head.

2-According to the Malays the cobra has a bright jewel on its head which shines at night, and snakes carry a jewel in their mouths for the possession of which they fight.

3- Chinese dragons that resemble snakes are said similarly to fight for a pearl.

4-The Sinhalese believe that certain serpents possess a jewel which is sovereign against snake-bite, and that snakes at night vomit up luminous stones ​which give them light.

5-Certain varieties of snake on the Lower Niger claimed to possess similar stones story which they vomit up. They are supposed to give a brilliant light, which attracts the snake's prey. they are mainly employed to cover the stones with mortar by those hunters, who are sufficiently adroit to kill the snake before it has had time to re-swallow the stone.

No animal documentary has ever recorded or report such claims. But We know of how rhino and elephant are been hunted by punchers for their horns. Similar thing would have happened to boa and other snakes if should diamonds stones actually exist.