Where the shape comes from
Three discs of jade threaded on a single cord: the three horizontals are the discs and the vertical the string running through them. The dot was added later to keep it apart from 王 "king", which has the same three-and-one frame with its bars unevenly spaced. On the left of a character the dot is dropped again, so the 王 in 玩, 现, 球, 理 and 班 is jade, not a king.
汉字 filed under 玉
No published character on HSK Guide is filed under this radical yet. 汉字库.