Andean blue opal
is a type of opal that occur is a blue-green color, sometimes with black dendrites.Has no play of colors.
The cause of color: the copper content in blue opal is up to 1% Cu, it is coloured by irregular microscopic inclusions of chrysocolla (Fritsch et al., 1999) or other Cu silicate. Galillou et al. (2008) states that the inclusions can be Mg-rich shattuckite.
It may turns milky after some times,and can be restored by immersion in water for a while,but it will be for a limited time, therefore must handle with great care.The stone is not treated.Today is difficult to find material with good tranclucency , and good piece became quite rare.
It comes from a unique location in the world: Andean Mnts: Acari Mine,Caraveli Province,Arquipa Department,Peru.