Made by: Sand
The rosette crystal habit tends to occur when the crystals form in arid sandy conditions, such as the evaporation of a shallow salt basin. The crystals form a circular array of flat plates, giving the rock a shape similar to a rose blossom. Gypsum roses usually have better defined, sharper edges than baryte roses. Celestine and other bladed evaporite minerals may also form rosette clusters. They can appear either as a single rose-like bloom or as clusters of blooms, with most sizes ranging from pea sized to 4 inches (10 cm) in diameter.
The ambient sand that is incorporated into the crystal structure, or otherwise encrusts the crystals, varies with the local environment. If iron oxides are present, the rosettes take on a rusty tone.
What is interesting is that the combination of sand and crystal varies with local environment. And it also shapes differently during different era. Hence, a desert rose can show the location of it and even the era when it formed.