🌈 Ever see rainbows in your crystals? In the sky these breathtaking displays of the visible spectrum can stop you in your tracks- and invite you to recall the rainbow lore we all know. Symbols of hope, luck, love from the heavens, and so on.
Amazingly, that color spectrum in the sky, is also seen (at a much smaller scale) in quartz crystals (by both natural and artificial means)! And not just quartz crystals. Calcite and fluorite also iridesce- projecting rainbow-like reflected color patterns.
Other common and well known iridescent minerals include labradorite and opal. But for this blog post, we're sticking with quartz rainbows.
So if you're wondering why you see rainbows in your quartz crystals (and perhaps unlock some wisdom from the process you can apply to your life) read on my friend.
Light waves bend (refract), bounce back (reflect) and spread out (disperse) as they speed up or slow down while traveling from one medium to another (so long as each medium has a different density). Like when light waves travel from air to liquid rain drops in the sky...
When white light waves transmit through an interface and spread out (dispersion)- the visible light spectrum breaks out into its ROYGBIV components and our eyes see rainbows!
Ways rainbows show up in natural quartz
Rainbows (and iridescence- subtle distinction but used somewhat interchangeable here) form naturally in crystals when light bends and disperses along internal structural surfaces.
There are two main modes for rainbow formation in NATURAL quartz crystals- 1. internal fractures 2. crystal surface growth. (Plus two more types that I'll mention as well.)
But first- you should know about human-induced iridescent quartz.
Lower-grade natural quartz crystals and clusters (usually not the clearest quartz) are modified to create artificially iridescent (and colored) quartz.
Sold as aura quartz, aurora quartz, opal quartz, angel aura quartz, flame quartz, and other names, these are simply natural quartz crystals with some (metallic) material artificially adhered to the surface.
Here's an example of an angel aura druzy quartz. It iridesces due to an artificial coating.
The thin surface coating bends, bounces and disperses light waves causing us to see iridescence. Now back to the mother-nature created iridescence and rainbows...
Mode 1: Rainbows from internal fractures in Quartz
Strain and stress under ground, temperature variations and damage during exhumation can all create tiny cracks within crystals. In quartz crystals these cracks are typically conchoidal fractures- which just means they're curved and typically have ringed ridges along the fracture surfaces. (Think broken beer bottle.)
When light passes through a quartz crystal- then through an internal fracture surface within the crystal- it reflects & disperses along this interface- shooting gleaming rainbow patterns back to your eyes.
These are sometimes called "crack rainbows"- not to be confused with Rainbow Crack (Which, apparently is the latest and greatest tool for hacking and cracking passwords)... or fracture rainbows.
Rainbows from internal fracturing are the most common type of quartz crystal rainbow. But they're sometimes hidden in plain sight.
To see these rainbows, the angles have to be just right. So if you've got a quartz crystal with an internal fracture surface, move it around in the light and look from all angles to see if a rainbow shows up.
Artificially fractured quartz- crackled, fire & ice
Like an ice cube cracks when you put it in hot water, quartz crystals are sometimes thermally shocked. After intense heating followed by rapid cooling, quartz crystals literally crack up.
These are commonly sold as "fire and ice quartz" and "crackle quartz." As you might suspect, cracked quartz shoots out plentiful rainbows if you're looking at it from the right angle.
Analogies for life
Fractured quartz crystals are "damaged". Yet, it's because of the "damage" that we see beautiful rainbows.
Perhaps we can allow rainbows from crystal fractures to remind us to keep going when times get rough. When we experience a loss or a failure and feel fractured, broken, damaged- we're simply re-shaping our internal structure.
And this life experience can act as a spring board- where we'll emerge radiating our full spectrum of magnificent colors. 🌈
Mode 2: Rainbows along sutured overgrowths in quartz
Have you ever seen a quartz crystal, where the faces are covered by several tiny quartz crystals- or even one smaller quartz crystal? It happens during a subsequent growth phase.
Also, sometimes smaller quartz crystals are incorporated within a larger quartz crystal. In those instances, the larger crystal formed with later crystal growth.
A density difference at the interface between two inter-grown crystals can cause the light to disperse and bounce back- causing... You guessed it! ...rainbows!
Here's an example.
3rd kind: Iris Quartz- Natural Iridescent quartz from India
Just want you to be aware of another form of naturally iridescent quartz, in case you come across it. This type is also called schiller quartz, anandalite, and adularescent quartz. Iridescence in these samples is unrelated to internal fractures or interfaces between multiple crystals.
These quartz crystals show natural iridescence on the smallest (z faces) on the crystal point (if you look down from the top you would see a 6 sided point with 3 small triangles (those are the z faces) and 3 larger point faces.
Laboratory testing and high resolution imaging shows micro- ridge and valley structures (etching) on the z-faces. That's what disperses the light and causes the iridescence.
The only known source for this type of naturally iridescent quartz is India.
Here's an example of what it looks like.
4th possible mode of natural quartz iridescense/ rainbows
Coating! Can't wrap up this blog without mentioning this one... Other mineral overgrowths (Typically goerthite and hematite) on the surface of quartz crystals form a thin sheen.
This sheen is transparent enough for light to pass through, but also causes reflection and dispersion of the light waves.
Want your own rainbow quartz?
You don't see rainbows in the sky every day. And you don't see rainbows in every quartz crystal. However, fracture rainbows and suture rainbows are seen occasionally in clear quartz, smoky quartz, rose quartz and citrine.
At Truth Minerals we've sold out of a collection of rainbow bearing quartz.
It was clear quartz from Arkansas, and of course- they're all locally and ethically mined- and hand selected by a geologist for quality and authenticity.
Check back soon (or better yet, sign up for our weekly emails) to find out when more rainbow quartz is available!