Alum — potassium aluminium sulphate — is one of the most ancient and multi-purpose natural compounds known to humanity, with a documented history of use stretching back to ancient Egypt and Greece across a remarkable range of applications including food preparation, traditional medicine, water purification, and skin care. In its natural slab or crystal form, alum is a white, slightly translucent solid with a distinctively sharp, astringent taste and powerful antimicrobial, astringent, and styptic properties. Lioncroft's Alum Slab is a quality product suitable for the range of traditional applications in which this remarkable compound is used.

In food preparation, alum has been used for centuries as a crisping agent in pickle-making, where a small amount added to the pickling brine helps maintain the firmness and crunch of cucumbers, gherkins, and other vegetables over prolonged storage. In traditional Indian and Ayurvedic practice, alum is known as "fitkari" and is widely used as a natural skin care and wound-healing agent — applied as an aftershave astringent to close pores and soothe nicks, used in the preparation of certain traditional cosmetic formulations, and valued for its antimicrobial properties in oral care. In water purification, alum acts as a flocculating agent, causing suspended particles to clump together for removal. Lioncroft's Alum Slab is a traditional, naturally occurring product of genuine utility across its many well-established traditional applications.