Negative Cyrstals with more dendritic features thatn usual in Tyndoll Figures.
A friend found them on the ice near where he lives. They were in S1 ice that as been enough thawing to develope a vertical pore structure. I suspect these formed when the pores froze into the ice in the mid level of the ice sheet. It might have gone a few days of cycling the melt layer melted and refroze. They are about an inch in diameter.
Several negative crystals that have the same orientation in a large crustal of S1 ice,