There are fewer than 6 species of Nautilus and they all are confined to the southwestern Pacific Ocean.
When you look at a Nautilus it is not obvious why it is called a chambered nautilus but if you cut it in half long ways you will see the spiral coils that make up the chambers. A nautilus has a natural creamy or whit in color with zebra like reddish brown stripes.
When they are alive the nautilus animals have around 90 tentacles and keep the chambers filled with gas. This gas keeps the nautilus floating upright so they can swim. this gas will cause the shells to wash up on distant beaches making their range seem further than it actually is.
Sometimes they polish the shell until the color comes off revealing the mother of pearl underneath.