Micas

Micas are early German handmade marbles (many with a faceted pontil, indicating manufacture before 1880) and are made of transparent glass with subsurface silvery mica flakes that take on the color of the matrix glass they’re submerged into.  Most common matrix glass colors are clear, various shades of amber or brown, various shades of blue from light blue to deep cobalt blue, and various shades of green from teal to dark army green.

Micas may sometimes be found to contain more than one layer of mica, and this is exceptionally unusual and appealing but it does not drastically increase the value of the Mica.  It’s easy to miss these – have to look.

Single pontil Mica Clouds are uncommonly found, and they are a premium of about 4x the price of similar 2-pontil mica.

Unusual micas are “cased micas,” meaning the mica flakes have been placed on top of the colored glass matrix so that it doesn’t take on the color of the matrix glass, and it’s encased in clear glass. These have vivid contrast of the mica against the base matrix color and are in high demand among collectors. Most commonly found cased micas are blue.

On occasion, other colors will be added to a clear mica such as streaks of transparent red, green or blue to add to the appeal of the marble.  These types of micas are rare and valuable.

Rare mica colors (listed in progressive rarity) are yellow, red, or black are extremely highly sought after marbles.  Black micas are usually cased in clear glass with the silvery mica flakes contrasting vividly against the black and maglights smokey grey usually, but not always.

Uranium yellow glass micas are ultra-rare.  They glow brightly under a black light.

Most common sizes are 9/16-7/8”.  Peewees of ½” or less are fairly common.  Any Mica over 1” would also generate a premium.  Micas of 1-1/4” or larger are rarely found and have increasing demand based on size.