The oxalic acid is a fairly stable molecule as organic chemicals go and the calcium hydroxide can be produced in basic ground water or in hydrothermal fluids. So all that is needed is a source of oxalic acid to produce the mineral whewellite. The source is undoubtedly organic and can come from coal or organic debris in sedimentary rocks. In deed, whewellite is found in some coal seams and sedimentary nodules and concretions. In the later occurrence whewellite would certainly not be considered a mineral due to its most non-geological origin but the other occurrences are all up for debate.
Color is colorless, white, yellow or brown.
Luster is vitreous to pearly. Transparency crystals are transparent to translucent. Crystal System is monoclinic. Crystal Habits include tiny acicular crystals and crusts. Specimens are found in hydrothermal veins, coal seams and in sedimentary nodules.