SEPTARIAN SPHERE - BEAUTIFUL PATTERN

SEPTARIAN SPHERE - BEAUTIFUL PATTERN

SIZE: 58mm

WEIGHT: 267.8g

ORIGIN: Madagascar

Hand polished.

Septarians were formed during the Cretaceous period, 50 to 70 million years ago. Decomposing sea life killed by volcanic eruptions, had a chemical attraction for the sediment around them, forming mud balls. as the ocean receded, the balls were left to dry and crack. Because of their bentonite content they also shrank at the same time trapping the cracks inside. As decomposed calcite from the shells was carried down into the cracks in the mud balls, calcite crystals formed. A thin wall of calcite was transformed into aragonite separating the bentonite heavy clay exteriors from the calcite centers. Because of this, the nodules are called septarians.
The name Septarian is derived from the Latin name, Septem, meaning seven. This relates to the fact that the mud balls cracked with 7 points in every direction, thereby creating the beautiful design.
Septarians are composed of Calcite (The Yellow Centers), Aragonite (The Brown Lines) and the Outer Grey Rock is Limestone. Occasionally the fossil or some of the fossils which started the formation of the rock is noticable in the rock.

This type of geode is sedimentary, which formed in an ancient sea floor about 50 million years ago. This is different from most geodes which are volcanic in nature. The septarian geode's golden star-like centers are the result of the crystallization of the mineral calcite, framed by aragonite. Some are filled in completely with calcite, while others left hollows showing the tooth-like calcite crystals and in rare cases, some perfect crystals of barite as well.