If you are fascinated by the hidden structures of our planet, you have likely come across
GONNARDITE. This mineral is a compelling subject for study, offering a unique glimpse into the complex chemistry that shapes the Earth’s crust.Whether you are a student identifying a hand sample, a researcher looking for crystallographic data, or a collector curious about a new find, this guide breaks down everything you need to know about
GONNARDITE. From its precise chemical formula to the geological environments where it thrives, let’s explore what makes this mineral distinct.
The Chemistry Behind the Crystal
Every mineral tells a story through its chemistry. At its core,
GONNARDITE is defined by the chemical formula
(Na,Ca)2[(Si,Al)5O10]·3H2O.This isn’t just a string of letters and numbers; it represents the precise recipe of elements that nature used to build this specimen. This specific chemical composition is what gives the mineral its stability and dictates how it reacts with acids, heat, or other minerals. It is the fundamental “DNA” that geologists use to classify it within the larger mineral kingdom.
Crystallography: Geometry in Nature
One of the most beautiful aspects of mineralogy is the hidden geometry within every stone.
GONNARDITE crystallizes in the
Tetragonal system.Think of this as the mineral’s architectural blueprint. It dictates the symmetry and the angles at which the crystal faces grow. Digging deeper into its symmetry, it falls under the
Tetragonal scalenohedral.
- Point Group: 4 2 m
- Space Group: I42d
Why does this matter? These crystallographic details are like a fingerprint. They influence optical properties—how light travels through the crystal—and physical traits like how it breaks or cleaves when struck.
Internal Structure and Unit Cell
If we could zoom in to the atomic level, we would see the “Unit Cell”—the smallest repeating box of atoms that builds up the entire crystal. For
GONNARDITE, the dimensions of this microscopic building block are:
a=13.21Å, c=6.62Å, Z=4
The internal arrangement of these atoms is described as:
Tektosilicates: tetrahedra are linked into 3-D framework with zeolitic H2O with chains of 4-membered rings, Al2Si2O10, connected by 5th Si; corner-sharing tetrahedra form chains // [001] spirally linked by extra SiO4 tetrahedra to form 3-D framework of 4- & 8-membered rings with large channels that lodge Na & H2O.2 Al-Si framework consists of □-ring chains along c axis, which are linked via outer tetrahedra of rings to other chains; along chains run channels containing cations & H2O molecules.3 Gonnardite, as recently defined (Artioli & Galli (1999)), has framework of natrolite (NAT), but (Si,Al) occupancy is disordered; cation contents ranging from nearly all Na cations (tetragonal natrolite) to as much as 35% Ca; singe xl refinement of tetragonal natrolite from Knibinsk alkali massif (Mikheeva et al (1986)) & gonnardite from Tvedalen, Norway (Mazzi et al (1986)) & Rietveld refinement of gonnardite from Gignat, France (Artioli & Galli (1999)) & tetragonal natolite from Mont Saint-Hilaire, Canada (Evans et al (2000) show that s.g. symmetry is I42d.4 Zeolites are alumino-silicate frameworks with usually loosely bonded alkali or alkali-earth cations, or both; molecules of H2O occupy extra-framework positions; gonnardite structure is similar to that of natrolite, but with Si,Al disordered, & usually with significant to substantial Ca.6 See “Additional Structures” tab for entry(s).5,7a,7b,8This internal structure is the invisible framework that supports everything we see on the outside, from the mineral’s density to its hardness.
Physical Appearance (Habit)
When you find
GONNARDITE in the field, what does it actually look like? A mineral’s “habit” describes its typical shape and growth pattern.
- Common Habit: Short to long prismatic macro crystals, striated; in stellate, interlacing groups; radiating fibrous, granular
- Twinning: On {110}, {011}, {031}
Twinning is a fascinating phenomenon where two or more crystals grow interlocked in a specific symmetrical pattern. If GONNARDITE exhibits twinning, it can be a dead giveaway for identification, distinguishing it from look-alike minerals.
Where is it Found? (Geologic Occurrence)
Minerals are the products of their environment. They don’t just appear anywhere; they need specific conditions—pressure, temperature, and chemical ingredients—to form.
Geologic Occurrence:
In cavities in amygdaloidal basalts, related igneous rocks, late forming; in granite, gneiss, syeniteKnowing this context helps geologists reconstruct the history of a rock formation. It tells us whether the rock was born from cooling magma, settled in an ancient ocean, or was transformed by the intense heat and pressure of metamorphism. For more broad geological context, resources like the
U.S. Geological Survey (USGS) provide excellent maps and data.
Related Minerals
No mineral exists in a vacuum.
GONNARDITE is often related to other species, either through similar chemistry or structure.
Relationship Data:
Zeolite familyUnderstanding these relationships is key. It helps us see the “family tree” of the mineral world, showing how different elements can substitute for one another to create an entirely new species with similar properties.
Frequently Asked Questions (FAQs)
1. What is the chemical formula of GONNARDITE?The standard chemical formula for GONNARDITE is
(Na,Ca)2[(Si,Al)5O10]·3H2O. This defines its elemental composition.
2. Which crystal system does GONNARDITE belong to?GONNARDITE crystallizes in the
Tetragonal system. Its internal symmetry is further classified under the Tetragonal scalenohedral class.
3. How is GONNARDITE typically found in nature?The “habit” or typical appearance of GONNARDITE is described as
Short to long prismatic macro crystals, striated; in stellate, interlacing groups; radiating fibrous, granular. This refers to the shape the crystals take when they grow without obstruction.
4. In what geological environments does GONNARDITE form?GONNARDITE is typically found in environments described as:
In cavities in amygdaloidal basalts, related igneous rocks, late forming; in granite, gneiss, syenite. This gives clues to the geological history of the area where it is discovered.
5. Are there other minerals related to GONNARDITE?Yes, it is often associated with or related to other minerals such as:
Zeolite family.
External Resources for Further Study
For those looking to dive deeper into the specific mineralogical data of
GONNARDITE, we recommend checking high-authority databases:
Final Thoughts
GONNARDITE is more than just a name on a list; it is a testament to the orderly and beautiful laws of nature. With a chemical backbone of
(Na,Ca)2[(Si,Al)5O10]·3H2O and a structure defined by the
Tetragonal system, it holds a specific and important place in the study of mineralogy.We hope this overview has helped clarify the essential data points for this specimen. Whether for academic study or personal interest, understanding these properties brings us one step closer to understanding the Earth itself.
