Rings of yellow and green were created by igneous activity nearer to the outer wall of the agate nodule as it formed. Centrally a blue-grey banded agate is separated by thinner bands of opaque white quartz. It appears in the middle part smaller bands of fortification agate rings were developing. A beautiful bowl created from an agate nodule once created by volcanic heat and pressure within the earth crust. The artisan using the natural lines of the raw rock to form this unique mineral bowl.
Silicon dioxide in a crystalline form is quartz. The tube or eye agate, referring to the unique patterning of this semi-precious quartz, which is also formed as a banded chalcedony and is naturally created in nature, chalcedony consisting of twisted crystal fibres which delight in there colour and numerous varied forms. The composition of these forms of agates is complex and leads to the many and varied types which are found all around the world.
Interesting mineral fact. The hardness of minerals measured by a scale of hardness developed by an Austrian mineralogist Friedrich Mohs. The arbitrary scale is that of on a number scale of one to ten, on a given place of any mineral that will scratch those of lower hardness. As a diamond will scratch glass, Topaz, for example, will scratch Agate. Agate is a chalcedony placed on the Mohs scale between six and seven. Some Agates have been claimed to be of greater hardness, as high as nine on the Mohs scale.
Agates are formed by volcanic action, agates develop in gaseous cavities within lava also found as the replacement minerals in sedimentary rock layers and clay stones. The Romans mentioned agates which they coveted. Agates have been discovered in use as adornments as long ago as seven thousand years and have been collected in modern times with intent by the Victorians since around the turn of the nineteenth and twentieth century.
The beauty of agates is obvious and is exhibited in the variety of colours, the multitude of banding and other forms within the banded and variegated agates in our range of finely polished freeform bowls. Freeform relates to the artisan's use of the free-flowing undulations of the raw agate material, allowing nature and flow lines of the stone to determine the shape and outcome of the finished object. The quality of the semi-precious agate from Madagascar is exceptional. Our tactile range of superb agate bowls will delight and intrigue on sight.