The only colors of the dyed Brazilian agates and geodes that don't eventually fade are the reds and blacks due to the processes used.

The Pinks, Greens, Blues and Purples fade with exposure to sunlight due to the chemical dyes used

The reds are greated by boiling the agates in a ferric iron solution and then heating to produce red ferris iron. This does not fade and is the same method used to produce most carnelian on the market today

The blacks/dark browns are produced by boiling in sugar water and then treating with sulferic acid to convert the sugar to carbon black. Its the same method use to produce most black chalcedony and to treat the Adamooka Matrix opal.

The magor problem with getting the natural geode/agates from Brazil is that the good quality agates are not as common as the pale agates with readily accept dyes. The work involved is the same but the profit is in the tourist trade so the magority of the work goes into collecting the lower grade agate for treatment rathen then the few collector agates.

Hope this helps

Bob Johannes
The Amethyst Rose

From Bob Johannes - July 17, 2006 at 09:16:18

Message: 47991