For a much more thorough description of the history of hand made glass marbles, please visit my History of Glass Making in Lauscha, Germany page.
Transparent Swirls can be found in size from 7/16" to well over two inches, though some are more restricted in their size range. Several factors can increase the collectibility and therefore the value of Transparent Swirls.
These changes sometimes left temporally sensitive indications at the level of the artifact.
The reader must appreciate that as one comes closer to the present the diversity of artifact types increases geometrically.
Naked examples, along with those possessing three levels, are rarer and therefore more collectible.
Examples with a left-hand twist are also more highly prized but often go undetected; these marbles have a twist to their design that goes to the right of the viewer, rather than to the left as is much more common.
However, the peak period of production was in the 1880s.
Agate was mined from Idar-Oberstein for centuries and evidence for actual agate mills dates to as early as 1454. In 1802, to counter the dwindling supply of locally procurable semi-precious stones, agate was begun to be imported to Idar-Oberstein from India.
The list below contains these and other inventions in China attested by archaeology or history.
The purpose of this guide is to provide a general introduction to some of the historic artifacts recovered from archaeological sites in the Upper Sangamon Basin of east-central Illinois.
Most of the field work has focused on the Mahomet area, but these sites are considered typical of material from the larger study area.
The historical region now known as China experienced a history involving mechanics, hydraulics and mathematics applied to horology, metallurgy, astronomy, agriculture, engineering, music theory, craftsmanship, naval architecture and warfare.
By the Warring States period (403–221 BC), inhabitants of the Warring States had advanced metallurgic technology, including the blast furnace and cupola furnace, while the finery forge and puddling process were known by the Han Dynasty (202 BC–AD 220).
They also made large mechanical puppet theatres driven by waterwheels and carriage wheels and wine-serving automatons driven by paddle wheel boats.