[4] Like other glass sponges, hexasterophorans have skeletons composed of overlapping six-rayed spicules.

In addition, they can be characterized by the presence of hexasters, a type of microsclere (microscopic spicules) with six rays unfurling into multi-branched structures.

[5][6] A living sponge is commonly firmly attached by its base to a hard substratum; less often rooted by the anchoring spicules and rarely inserted directly into the loose bottom sediments.

The oldest order, without fused spicules, is Lyssacinosida (or Lyssacinosa), which appears in the Ordovician.

The most fused order is Lychniscosida (or Lychniscosa), which develops octahedral frames (lychniscs) around the nodes between their dictyonal strands.