- Chemistry: (Ca, Na2, K2)Al2Si10O24
- 7H2O, Hydrated Calcium Sodium Potassium Aluminum
- Class: Silicates
- Subclass: Tectosilicates
- Group: Zeolites
- Uses: Mineral specimen and chemical filter.
Mordenite is one of the rarer, but still somewhat more widespread, members
of the zeolite group of minerals. Zeolites are a popular group of minerals
to collect because they are so beautiful and because they contain such
diversity in color, crystal form and rarity (some are very common and easy
to collect and some are rare and a pleasure to finally own). Mordenite
belongs to this last category.
Zeolites have an openness about their structure that allows large ions
and molecules to reside and actually move around inside the overall framework.
The structure actually contains open channels that allow water and large
ions to travel into and out of the crystal structure. The size of these
channels controls the size of the molecules or ions and therefore a zeolite
like mordenite can act as a chemical sieve, allowing some ions to pass
through while blocking others.
Mordenite forms fine sprays of radial acicular crystal clusters that
look like pin-cushions or snowballs. On top of other interesting and beautiful
associated minerals, mordenite can be extremely striking. Mordenite is
definitely a must have especially for the dedicated zeolite collector.
Color is colorless, white, yellow, pink and red.
Luster is vitreous to silky and pearly.
Transparency: Crystals are transparent to translucent.
Crystal System is orthorhombic; 2/m 2/m 2/m
Crystal Habits include sprays of radial acicular crystal clusters
that can remind someone of pin-cushions or snowballs. Individual crystals
are prismatic to acicular and striated vertically. Aggregates can be radiating,
fibrous, columnar and encrusting.
Hardness is 4 - 5.
Specific Gravity is approximately 2.1 (very light)
Streak is white.
Associated Minerals are quartz,
and other zeolites.
Notable Occurrences include Morden (hence the name), Kings Co.,
Nova Scotia, Canada; Hoodoo Mountains, Wyoming and Arizona, USA; Val dei
Zuccanti, Italy and Poona, India.
Best Field Indicators are crystal habit, color, low density