Which crystals are known to have a coffin lid appearance?

Struvite crystals, also known as triple phosphate crystals, are recognized for their characteristic coffin lid appearance. This distinctive shape is due to their hexagonal form that resembles a lid of a coffin when viewed under a microscope. Struvite crystals typically form in alkaline urine and are associated with urinary tract infections, particularly those caused by urea-splitting bacteria, such as Proteus species. These bacteria raise the pH of the urine, facilitating struvite formation.

This identification is important in a clinical setting, as the presence of struvite crystals can indicate a urinary tract infection that may require treatment. Understanding the morphology of these crystals can aid in the diagnosis and management of related urinary conditions.