Sunday, September 6, 2015

agates

Here are two more of the 1976 gemstones stamps from Botswana. 
Agate forms when gas bubbles trapped in solidifying lava become filled with alkali and silica bearing water.  The alkali attacks the iron in the surrounding lava and bands of the resulting iron hydroxide are created in the gel which loses water and crystallizes, leaving the bands intact. 
Pink Agates are unique to Botswana
and Moss Agates aren't a true agate since they don't have the banding pattern, but they are traditionally known as agates since they have more than one colour. 
Looking at these gemstones in their raw state, it can be difficult to imagine how they would look in a polished state. 

or,
in the hands of a very skilled jeweller
moss agate brooch made around 1908-1917, $25,000

see more gems from around the world SundayStampsII

3 comments:

  1. I like browsing in gem shops, it's amazing the variety of things that can be made.

    ReplyDelete
  2. These stamps would look somehow strange on an envelope, but I like them.

    ReplyDelete
  3. The gemstones in my wife's rings are smaller than these - thank goodness. Agates are always attractive when polished,even if the ones I had to polish as part of a mineralogy course were not so good.

    ReplyDelete

Glad you stopped by. For anyone who stumbled here, don't be shy to say 'hi' and let me know you've visited!