Wednesday, October 11, 2017

DO YOUR CABOCHON STONES CONTAIN METAL?

You know how you sometimes see a stone or cabochon and say it has metal in it?  Maybe yes . . . maybe not exactly.

Here's the skinny on how to tell the difference. 

METAL- (Naturally occurring) consists of a single atomic element, like iron, copper, etc.
MINERAL - a combination of several elements and is generally crystalline, some of which can be processed into metal.

Right now, you're thinking to yourself, "Of course, I always go to to the atomic level of identifying the inclusions in my rocks." Relax. If you identify a streak of hematite as iron, you're right for your lapidary purposes. We're not evaluating the metal/mineral content to ascertain whether it can be profitably mined, we're helping those who love our work understand what they're seeing.

COPPER -  A Metal

For example, check out this nifty copper cabochon with an epidote matrix (according to the vendor I purchased it from) has the copper peeking through it.
 I've heard that this kind of specimens can sometimes have quartz in it, which would have lightened its look a bit, but all in all, I like the blue-green

TIGER IRON - Mineral

However, this Tiger Iron cab? Not exactly. 




The first time I saw a slab of Tiger Iron, I thought it was a very poor quality of Tiger Eye. But I was wrong.

Tiger Iron is a separate kind of mineral that combines Tiger Eye and Hematite in random patterns. Hematite itself, is a form of Iron Oxide which is where the "Iron" in Tiger Iron comes from. Depending on the amount of Hematite vs Tiger Eye, it can be very attractive. However, I prefer a lot more Tiger Eye than Hematite, so this isn't a favorite among my cabochons. The dark overwhelms the chatoyance. I see this from time to time at rock shows, but if I'm doing the buying, I'll get straight Tiger Eye any day.


PYRITE  - Mineral

I admit I love this cab!  It's quartz with pyrite  embedded in it. Because of the orange in the quartz and the shapes of the markings, it looks a lot to me like a magical fire. I wasn't able to catch the flash from the pyrite in a picture, but it's very impressive in person.

The Pyrite is a mineral (Iron Sulfide) and it's also known as "Fool's Gold". In some settings, like this, it actually looks more like the Iron it contains than gold, but if you've seen pyrite crystals, you understand where the name originated.






RUTILE - A Mineral

 When I first started admiring Rutilated Quartz, I thought that the different colors of the thin lines meant that they were different materials. Not so. According to Mindat.org, Rutile (TiO2) comes in Blood red, brownish yellow, brown-red, yellow, greyish-black, black, brown, bluish or violet.

Oxides are actually found in many stones. In rutilated quartz, the rutiles  can be made of tin oxide.   That's the same stuff in the white paste lifeguards at the beach smear on their noses to prevent sunburn. More importantly, in its dry form, it makes a wonderful lapidary polish.




Do you have any inclusions that you want to identify as either metal or mineral? Send me the information and a picture and I'll see what I can do to help you identify it.

In case you missed it, the cabochon from the last blog post was identified by  Burton Rondo as Bacon Opal with Hyalite, so he won!  A cab of the material is on its way to him!

Until next time,

Your Lapidary Whisperer,

Donna

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 www.LapidaryWhisperer.com 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!
WIN THIS CAB!

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,

Donna