Okay, so, Labradorite. Labradorite is complicated and sciencey, as all good rocks are. I’ll see if I can explain it in a way that makes any sense! (Once again, I’m not a scientist! Correct me if I’m wrong!)
Most minerals, when they’re bright and pretty and colorful, look like that because while they were forming some impurities got mixed into them – usually metals like iron, copper, or titanium. Without any impurities, these rocks would naturally be colorless. We call these guys allochromatic (other-colored).
Other gemstones are certain colors because those elements are an important part of how they formed. They’re not impurities that got mixed in, they’re actually part of the gemstone. Their natural color IS the color you’re seeing. We call them idiochromatic (inherently colored).
But labradorite doesn’t get its color from either of those things. Labradorite is special. It’s part of a third group: psudochromatic (false colored). These rocks aren’t colorful at all, but they LOOK that way when light passes through them.
See, labradorite is actually just… grey. From most angles, it looks like this:
You have to look at labradorite from a pretty specific angle to get those flashy colors, so when we cut it into cabochons for jewelry, or just polish up big pieces of it, we’re careful to do so at the most flattering angle, the angle that shows the most schiller, or “those cool glowy colors.”
Why just the one angle? It’s all about labradorite’s crystal structure, and how it’s formed.
Labradorite is a rock that cooled down really slowly. Because of that, it’s made of lots of very very thin layers of crystal, stacked on top of each other and all pretty much aligned in the same direction. These are alternating layers of albite (mostly sodium), and orthoclase (mostly potassium), which solidify at very slightly different temperatures. Labradorite is a rock that cooled in just the right way for a thin layer of albite to form, then a thin layer of orthoclase, then another thin layer of albite, and so on.
When light hits labradorite at the perfect angle to pass through a bunch of these layers, you get the schiller effect. Basically, a little bit of the light gets bounced off the first layer and back to your eyes. The rest of the light passes through to the second layer, and a little bit gets bounced back to your eyes again, and so on. Every time more light gets sent back to you, it’s a little out of sync, and this makes it look like a different color.
(This is a very simplified way of explaining this.)
If these layers were all perfectly the same size, you’d get a uniform color, like the blue in moonstone. But in labradorite, these layers might be different widths in different places, so different parts of the stone will reflect back wildly different colors! We call this effect labradorescence to differentiate it from the uniform colored adularescence found in moonstone and some opals.
Depending on where it’s found in the world, labradorite can reflect all sorts of different colors!
But whatever color it is, Labradorite will always be the Best and Coolest Rock.
Shiny rock science!
I’ve actually started collecting labradorite specimens.
lepidolite is a variety of mica and is typically pink or lavender colored. when tumbled it is extremely glittery – pictures don’t do it justice!
2) ulexite
ulexite is also called “tv rock” and has a super unique optical effect – when placed over something it displays that image onto the top of the rock. it’s not merely opaque – the fibers within the mineral literally project an image onto the surface of the stone.
3) pietersite
pietersite has chatoyancy – much like tiger’s eye – that creates movement and shine through the surface of the stone. however, unlike tiger’s eye, pietersite’s chatoyancy is in swirls instead of straight lines. it’s incredible to behold – i recommend looking up pietersite on youtube and checking out videos of it under good lighting.
4) optical calcite/iceland spar
this type of calcite is actually completely clear, but refracts the light going through it in ways that create rainbows and other neat optical effects. isaac newton himself actually studied this rock to help better understand the nature of light itself & the phenomenon of optical illusions.
5) alexandrite
alexandrite is a variety of chrysoberyl that exhibits a color change! it changes from a greenish hue to a brilliant red depending on the type of light and the source. the color changes in alexandrite are phenomenal and rarely seen in other stones.
6) spectrolite
don’t let the image fool you – this stone is actually pure black. the brilliant colors it exhibits are just a flash (it’s actually called labradorescence, which is what the stone labradorite is named for). spectrolite is an uncommon form of labradorite mined only from finland. some varieties of high quality labradorite from madagascar can show a spectrolite play, but nothing is as dark with as brilliant a flash as spectrolite.
7) specular hematite
specular hematite is a variety of hematite that has a beautiful, glimmering surface especially when polished. much like lepidolite, the shimmer of specular hematite is caused by mica.
8) boulder opal
boulder opal is ironstone with cracks of brilliant natural opal running through it. these formations are entirely natural. opal has the most brilliant and vibrantly colored flash of any other stone.
9) enhydro quartz
enhydro quartz is a variety of quartz that was formed with naturally occuring water & air bubbles within them! in some specimens the water bubbles will actually move underneath the surface of the crystal.
10) fire agate
fire agate is actually a form of chalcedony, and is well known for having a beautiful rainbow effect caused by schiller, rather than flash or labradorescence.
