THE MINERAL LEIFITE
- Chemistry: Na6Be2Al2Si16O39(OH)2 - 1.5H2O; Hydrated Sodium Beryllium Aluminum Silicate Hydroxide Fluoride.
- Class: Silicates
- Subclass: Tectosilicates
- Uses: Only as a mineral specimen.
Leifite is a rather rare and obscure beryllium silicate mineral.
It forms in rare rocks known as agpaites
which are igneous
They are characterized by high concentrations of alkali metals especially
sodium and low concentrations of silicon and aluminum.
They are feldspar
being low in silicon, contain little or no
Agpaite pegmatites contain unusual minerals because they originate with unusual elements.
Elements such as beryllium, zirconium, titanium, niobium, barium, strontium, thorium and
rare earth metals are all found in the compositional mix that represents this rock type.
There exists agpaite in several places around the world, but by far the most famous are
the ones at the Kola Peninsula in Russia, Narsarsuk, Greenland and the one above all the
rest, the mines of Mount Saint Hilaire, Quebec.
Leifite is one of the rare minerals that can form in these silica starved, unique
Other minerals coming from these unique localities include
analcime to name a few.
- Color is white or colorless.
- Luster is vitreous.
- Transparency: Crystals are transparent to translucent.
- Crystal System is trigonal.
- Crystal Habits include prismatic to acicular crystals with a hexagonal
cross-section and a basal termination. Crystals are striated lengthwise.
Aggregates are clustered into radial sprays.
- Hardness is 6.
- Specific Gravity is 2.6
- Streak is white.
- Associated Minerals are
aegirine and other rare minerals.
- Notable Occurrences include Narsarsuk, Greenland and Mount Saint Hilaire, Quebec.
- Best Field Indicators are crystal habit, locality and hardness.