Which order contains the stony corals that form much of modern reef framework?

The order containing the stony corals that form much of modern reef framework is Scleractinia.

Scleractinians are also called stony corals or hard corals. Individual animals called polyps secrete calcium carbonate, usually in the mineral form aragonite, creating cup-like skeletons called corallites. In colonial species, repeated budding produces connected colonies whose accumulated skeletons become substantial reef structure.

Many reef-building scleractinians live in warm, clear, shallow water and host photosynthetic dinoflagellates traditionally called zooxanthellae. The symbionts provide energy that helps the corals grow, although not every scleractinian is a shallow-water reef builder. Some solitary or colonial species live in deep, dark water and do not form tropical reefs.

The distractors belong to different cnidarian groups or describe different animals: Pennatulacea includes sea pens, Actiniaria includes sea anemones, and Alcyonacea includes soft corals. Scleractinia also lacks the jellyfish-like medusa stage found in some other cnidarians.