Wednesday, September 27, 2017

Win This Cabochon!

Notice the silver orbs on the far right and center. It's also easy to see the swoops of black rocks.

I've come into some of the most fascinating material, but I can only make a very vague guess of what it is.  

So, I'm offering this cabochon free to the first person (with a U.S. Postal Address) who writes in the Comments section of my blog page and tells me where it's from and what the heck is going on in the clear agate. This cab is 25 x 16 x 5 mm and is polished on the back.

It was described to me as "old stock" from somewhere in the western U.S. I'm pretty much convinced that old stock means "I inherited it and have no idea where it's from".  It's obviously a remarkable gold/brown plume, which seems to me is not only an usual color, but might help place where it was collected.

The agate is as clear as glass . . . and then . . . it's full of stuff.  

There are what look like silver orbs at various places in the clear agate. So far, so good. But, when I cut and polish it, there's no sign of the orb bits on the edges. What caused them and where do they go when I polish them?  With many similar features, you'd expect to at least have a small hollow place where the orb hits the edge. Not here! There are, however, some small voids in the plume parts.

Another hint is that when I look at a slab of the material, there are bumps where the agate has a gap before the top lining. They look a bit botryoidal, but not really, if you know what I mean. They're too separated where botryoidal elements sort of pile on each other like a bunch of grapes. It would appear they have something to do with the bubbles, but there's not clear connection.

Notice the clear bumps hiding under the burgundy layer.

Then there's the really cool, almost microscopic black bits.  They swoop around like bits in a river. They also cover some of the plumes.  Notice the cut edge showing the black stuff around the end of a bit of plume. Why do they cling to the plume material but not the silver orbs?

Finally, there are planes on the top half of the clear agate. They remind me of a fried marble (yes, I'm showing my age--and I still have mine!). I really expected that area to crumble off when I shaped and polished it, but it's solid. Again, how and why?
My Fried Marble!

I'm very curious about this rock, and I really want to know where it is from and what is going on with the clear agate.  I suspect that someone who sees this will show it to a collector friend and ask, "Don't you have a garage full of this stuff?" I hope so.

This is one time that my love of making up stories to go with stones doesn't work. I'm hoping for facts. So if you've ever seen this stuff, let me know. If you're the first one to get the facts to me, I'll send you the cab at the top of the blog post as a thank you!

Until next time,

Your quizzical Lapidary Whisperer,


Wednesday, September 13, 2017

The Eyes Have it - Chatoyant minerals

 As a lapidarian, my favorite chatoyant stones to work with are pietersite and tiger eye. They both provide a lot of flash, especially in cabochon form and they're not as picky about angles as I've found laboradite to be. They also both take a nice polish which adds to the flash of the chatoyance.

One of the reasons I love working with pietersite is the way the waves of parallel fibers fold back and forth over themselves, creating unique patterns like on this blue specimen. The material is pricey, but I love to treat myself to a piece now and then. Wouldn't you?


Chatoyance (Sha-toy-ance) is a delightful word that rolls off the tongue. It comes from the French word chatoyer, meaning shine or luster. It's probably no accident that the first four letters "chat" mean cat in French and the cats eye effect in minerals is called chatoyant. You'll hear a lot of rockhounds and lapidary artists refer to it as the 'flash' in the stone, because it only shows that remarkable shine when the light hits it just right

This beautiful reddish tiger eye is nothing to look at  in normal light, but put it in the sun and you get flashes of light called chatoyance. Tiger Eye is one of many stones that share this characteristic.  Chatoyance occurs when fibers in a stone line up parallel to each other, at least in a segment. The shine/flash is always perpendicular to the fibers.

This tiger eye that was in a different blog posting. I love the way it demonstrates how bright the flashes can be.              


This not very attractive stone is a slab of labradorite I photographed in indirect light. You can see there are some different colors, but it's not anything to get excited about.

However, you can see the same stone below photographed in sunlight, and the chatoyance creates flashes of dramatic colors. The secret to working with it is to be sure to get that flash on the face of the cabochon. I see it used a lot by wire work artists where the shine of the silver adds to the effect.

Charoite is listed as a chatoyant mineral, and I've seen some that is, but this cab of mine really isn't. Part of the problem is that not all charoite has bands of parallel fibers. Since the flash happens when the fibers are not parallel to the base and these fibers are completely disorganized, it doesn't flash at all for me.

At the same time, it is still a gorgeous purple cab and the white fibers add a lot of interest.

Have you ever made cabs with chatoyant minerals?  I'd love to see some pictures of you work!

Until next time,
Your Lapidary Whisperer,