Those spawning crystals are just chunks of ice rolling over the top of each other. For a similar effect, maybe try pushing a mound of loose Legos around and see what colors pop-up.
Here’s a video of this same phenomena on Lake Superior - wind blown waves washing up thin shore ice. It’s stunningly beautiful and makes a lovely sound. Some years, it can build up to be almost five to ten feet thick in some areas. Superior has a steep, rocky shore so it builds up. Mille Lacs (pronounced Muh-Lac if you’re from northern MN) has a shallow, sandy shore so there is potential for “attack”.
