As far as I’m aware, the term Nirvana Ice was first used to describe Quartz with growth interference patterns that was found about 15 years ago in the Himalayas, where the glaciers had melted back.
This formation occurs when Quartz forms with other minerals such as Calcite, Anhydrite, Fluorite that then disappear. The Nirvana formation has since been found in Amethyst and Fluorite, that I know of, and in other locations in the world.

These pieces have a powerful energy. They are very light and airy with a high vibrational frequency. I’m very attracted to them and have kept one for myself to learn more about.

Generally, Fluorite calms and settles the mind and is good for meditation, spiritual growth and increased psychic awareness.  It cleanses the aura and gives protection by clearing negative thought patterns and transmuting all negative energies. It can bring a little distance in times when emotions overwhelm us, so that we can see both what needs to be done and what needs to be healed.  It is also excellent for concentration and focus, and is an excellent gift for students.

Fluorite occurs in many colours; all fluorites share the above properties, but each colour emphasises certain characteristics.

Green fluorite is very cleansing and refreshing and healing to emotions and mind. It helps to bring mind and emotions into balance and harmony within us.