capped column

capped column

[′kapt ′käl·əm]
(hydrology)
A form of ice crystal consisting of a hexagonal column with plate or stellar crystals (so-called caps) at its ends and sometimes at intermediate positions; the caps are perpendicular to the column.
References in periodicals archive ?
New oversized, industrial design windows, 13' high floor slabs with mushroom capped columns and new in-lobby coffee bar will provide an exciting and creative work environment in contrast to the surrounding new glass skyscrapers.
Snow crystals can also come in shapes like simple prisms, simple needles, capped columns, hexagonal plates, and more.
The rarest kind of snowflakes are called capped columns. They're also known as wheels or spools, because that's what they look like.