What is a ice particle?

By Ice Particle, I assume you mean the smallest unit of ice that is still ice. That's called a Meson. A Mesons is one type of Hardon; the other is Baryon. Baryons are found primarily in steam.

A meson is the basic building block of ice molecules. It is composed of a quark and an anti quark. Quarks have properties like spin, charge, top/bottom, flavor and strangeness. The interaction of these properties is what gives each meson its unique characteristics. For example, a Strange and Charming meson might become a snowflake.

Based on this, you might think that a quark is the smallest unit of ice. It's not. A single quark isn't ice any more than an Oxygen atom is Air. In order for it to behave like ice, a quark needs to be part of a meson.

I hope this helps. If this answer is confusing, be sure to check the Wikipedia articles on Mesons and quarks. I found them very informative.