How do I identify Natrolite?

Natrolite can be identified by its hardness of 5 - 5.5 on the Mohs scale, White color, Pearly, Vitreous luster, Orthorhombic crystal system. Look for these key characteristics when examining specimens.

What color is Natrolite?

Natrolite typically appears in White, Colorless, Red, Yellow, Brown, Green, bluish. Color can vary depending on impurities and formation conditions.

How hard is Natrolite?

Natrolite has a hardness of 5 - 5.5 on the Mohs scale. This gives it moderate hardness.

Natrolite

A variety of Natrolite Subgroup

Rare

Natrolite specimen - rock identification

What is Natrolite?

Natrolite is a whitish mineral that can occasionally produce striking and distinctive crystal formations. Long, slender clusters of crystals radiating out from a central point give it a sea-urchin or puff-ball-like appearance. Such exceptional specimens are prized by collectors. Occasionally, natrolite is also used commercially in water purifiers and chemical filtration systems.

Etymology & Origins

It was named natrolite by Martin Heinrich Klaproth in 1803. The name is derived from natron (νατρών), the Greek word for soda, in reference to the sodium content, and lithos (λίθος), meaning stone. Needle stone or needle-zeolite are other informal names, alluding to the common acicular habit of the crystals, which are often very slender and are aggregated in divergent tufts.

Uses & Applications

Natrolite can be used to purify water or filter chemicals from other materials. It is also used as a gemstone, and the striking forms its crystals can take are quite beautiful; large crystals of natrolite are highly prized by collectors.

Healing Properties

Natrolite is believed to be a powerful stone in the practice of Reiki, harmonizing the body's energy and kick-starting physical and emotional healing. Excessive bloating may benefit from natrolite, and it might encourage active toxin removal. The stone's particles are supposedly so tiny that they can infiltrate the body's cells, which is how they remove toxic components.

Optical Properties

Refractive Index: 1.478-1.493
Birefringence: 0.012-0.013
Pleochroism: None
Optical Character: Biaxial positive

Natrolite Market Value Calculator

Estimate the market value of Natrolite using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.

Natrolite Localities Map

See where Natrolite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

Map preview

North ZoneCentral RidgeSouth Basin

Key Characteristics

Rock Types of Natrolite

Several varieties of natrolite have been distinguished by special Nips. Fargite is a red natrolite from Glenfarg in Perthshire. Bergmannite, or Spreustein, is an impure variety which has resulted by the alteration of other minerals, chiefly sodalite, in the augite syenite of southern Norway.

Characteristics of Natrolite

Larger crystals most commonly have the form of a square prism terminated by a low pyramid, the prism angle being nearly a right angle. The crystals are tetragonal in appearance, though actually orthorhombic. There are perfect cleavages parallel to the faces of the prism. The mineral also often occurs in compact fibrous aggregates, the fibers having a divergent or radial arrangement. Natrolite is readily distinguished from other fibrous zeolites by its optical characteristics. Between crossed nicols the fibers extinguish parallel to their length, and they do not show an optic figure in convergent polarized light. Natrolite is usually white or colorless, but sometimes reddish or yellowish. The luster is vitreous, or, in finely fibrous specimens, silky. The specific gravity is 2.2, and the hardness is 5.5. The mineral is readily fusible, melting in a candle-flame to which it imparts a yellow color owing to the presence of sodium. It is decomposed by hydrochloric acid with separation of gelatinous silica.