Septarian started their life as a ball of mud… During the Cretaceous period these ancient mud balls dried and cracked before mineralisation occurred. For those who like a little more detail, calcite leeched into the cracks forming calcite crystals on a layer of aragonite. The bentonite clay surrounding this was eventually replaced with limestone turning the ball of mud to stone. They are found in Madagascar and Utah, USA.
With a hardness of 3.5-4, it is best suited to pendants, earrings and brooches with care being needed in rings, bracelets and cufflinks.
Hardness – resistance to scratching and wear
Stability – resistance to alteration by light, heat or chemicals
Toughness – resistance to fracture, cleavage or cracking
Please note you will receive the stones in the photograph