One is whether or not there are alternating colors in the core, and another is the appearance of the core itself, specifically how well defined the lattice is.Solid Core Swirls come in several different forms, though the one pervasive trait all have is that the core appears solid, with no or at the very most minor openings.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.However, most have such an outer layer and this almost always consists of either single colored strands or multicolored bands.
End-of-cane examples have a design that terminates somewhere inside the marble without reaching the other side; since they are the last marble off the cane there will only be one pontil, and it is from this that the design originates.
On rare occasions there will be two colors in the core, and usually these colors alternate.
The colors are typically opaque, though translucent strands do occur, especially in white examples.
Hand made glass marbles were invented in Lauscha, Germany, in the late 1840s.
They were produced until the early part of the twentieth century, when World War I and the invention of marble producing machinery in America effectively ended the hand made marble industry.