These can affect its color, giving it a range of hues, including blue, green, red, lavender, black, orange, and even yellow. Calcite can be transparent, translucent or opaque. Renee Birchall is a ...

By 2012, the alert level for the region was raised from green to yellow, signaling heightened activity but not ... When these hot, acidic fluids interact with calcite in the rocks, they can release ...