There's no single, fixed number of water molecules that bond together to form an ice crystal. It's more about the arrangement and interaction of many water molecules. Here's why:

* Ice Crystals are Complex: Ice crystals are highly organized structures. Water molecules form a hexagonal lattice (think of a honeycomb), with each molecule forming four hydrogen bonds with neighboring molecules.

* Size and Shape: Ice crystals can range in size from microscopic to macroscopic (think snowflakes). The number of water molecules forming a crystal depends entirely on the size and shape of the crystal.

* Growth and Change: Ice crystals grow and change as they encounter different atmospheric conditions (temperature, humidity, etc.). This growth process involves the addition of more water molecules to the existing lattice.

In short, while we can't give a specific number of water molecules for an ice crystal, it's a fascinating process where countless molecules cooperate to create these beautiful and intricate structures.