In this case, macphersonite is an orthorhombic mineral while leadhillite is monoclinic in symmetry. There actually is another mineral that has the same chemistry and a different structure from these two. The mineral is called susannite and is trigonal in symmetry. This makes macphersonite, leadhillite and susannite a complete set of trimorphs . All three minerals could be classified as sulfates due to their sulfate ion, but are here classified as carbonates due to the greater number and therefore more significance of the carbonate ions.
Color is colorless, white, amber or brownish.
Luster is adamantine to resinous. Crystals are transparent to translucent. Cleavage is perfect in one direction. Fracture is uneven. Streak is white.