Amethyst Geodes: Exceptional Colour
Two impressive amethyst geodes with deep purple crystals. Both pieces were individually chosen for our collection.
A geode is a rock with a hollow cavity where crystals have grown over millions of years. These cavities form in volcanic or sedimentary rocks.
As mineral-rich groundwater seeps into the cavity, dissolved silica is deposited, which slowly crystallises into quartz.
The amethyst crystals tend to be smaller if growth stopped earlier. This may be because the supply of mineral-rich water decreased or ceased completely.
The first deposits are often layers of chalcedony, followed by clear or milky quartz.
Trace amounts of iron, combined with natural radiation from surrounding rocks, produce the purple colour.
Where these conditions are not present, the quartz remains colourless or white, or develops a less intense shade of purple.
These premium-grade amethyst geodes are from Uruguay.
Details
1. (on the left in the first photo) 430g | 14 x 8cm £81.69
2. 494g | 15 x 8.3cm £93.85
