Sunday, July 5, 2020




Green Tree cabochon on a shell



 Green Tree Agate is an absolute delight to work with! With a Mohs hardness of 6.5 to 7, it takes a bright polish, which I always find satisfying.  

 At first glance, it's easy to understand why "agate" isn't the first thing that comes to mind when you see it.  The color is milky white, with no translucence. Also, it's not banded, but it is microcrystalline silicon dioxide, and it is still considered a member of the agate family. 


Goose in the Garden




This piece of Green Tree was unusually pitted and I was just horsing around with it when a Goose appeared. He's looking left and I don't think he's very happy.









Then there are the green patterns. Sometimes, they're called "mossy", but in reality, they're dendritic. As far as the color goes, it's not the copper I first thought. It is a combination of manganese and iron oxides. 


Those dendrites are what make this stone so much fun to work with. It's almost like watching clouds in the sky, as you look at it, different shapes and stories come alive.  That's the good news. The not-so-good news is that unlike bands in agate, dendrites are in constant motion throughout the rock. The story you see on the slab can easily disappear or become a whole different story as you shape it.


Blowing Tree



When I was making the cabochon at the left, I saw a green sapling in the forest bending over in a storm.



Frozen Creek








I especially love the almost-clear quartz and the darker white material in this cab, to me it looks like a half-frozen stream with evergreen trees along the shore. What do you see? 

 Green Tree agate is most commonly found in Brazil, India, and Uruguay and other colors of dendritic agate can be found in other areas of the world including the U.S.




While I love writing the blog, and have since 2016. I find I must take a break from it for a bit. Thanks for your attention and comments. I really appreciate them.  If you have a lapidary topic you'd like me to cover when I restart, please let me know by responding in the Comments section or write me directly at




Donna, Your Lapidary Whisperer

Friday, June 5, 2020


Since Mariposite is from Mariposa, CA, shouldn't Chinese writing rock come from China?


But Chrysanthemum stone does come from China!

Both stones, primarily limestone with with andalusite crystals are rightly called Porphory (igneous rocks that have phenocrysts - large crystals or grains). The limestone is usually dark gray with a slight greenish undertone. The crystals can be close to the color of the limestone. The ones that make for the best contrast for lapidary are white or clear; giving good contrast.

Cab I made with Chinese Writing rock

Chinese writing rocks were first found and described in the 1960's when it was uncovered during road construction in the Sierra Nevada foothills near Auburn, CA. People who saw it thought the random crystal structure imbedded in the base rock resembled characters from Chinese writing, and they really do.

The slab I made this cab from is stained with another mineral. Iron?

Chinese Writing Rock I found in river rocks

This is a Chinese writing rock I found in a bunch of river rock. It has the normal green tones. I keep this one on my desk because I think of it more as a thinking rock, trying to figure out what the shapes might be.

High Quality Chrysanthemum stone Bing Image

Chrysanthemum stone, on the other hand, is found in the Hunan Province's Yangtze River Valley in China. Aside from the geography, the characteristic that divides them is that the dandalusite crystals in the Chinese writing rocks are exceedingly random, the ones in the Chrysanthemum stone are centered with the crystals spraying out in a floral pattern resembling the chrysanthemum flower.

Chrysanthemum stone/yard rock

This, on the other hand, is poor quality Chrysanthemum stone. You can see the flower formations, but they are unclear and unfinished. I got this one at an estate sale for a former rock hound.


My club shop has been closed for a while because of Covid-19, so even if I wanted to harvest a slice off my not-terribly-good-quality Chrysanthemum yard rock, my 10" rock saw couldn't handle it. So my comments will be based on some Chinese writing rock I've managed to acquire.

The Mohs hardness of the stone can range from 5-7, which will have a significant impact on how well it polishes.I've seen other lapidaries do marvelous things with it, but I don't get a lot of satisfaction from the little I've done, like the cab at the top (which I had to use spray sealer to give it a polish--it just looked dead).

So while I love looking at them, neither Chinese writing rock nor Chrysanthemum stone are items I search out.  In fact, if I had a piece like the high quality Chrysanthemum stone above, I'd keep it as a specimen. It's beautiful!

Until next time,

Your Lapidary Whisperer,


Tuesday, May 5, 2020


While many of our favorite rock shows, stores, and club meetings are shut down to prevent the spread of COVID -19, it's a good time to dig through our personal stockpiles and work on them at home.

And, if you're like me, you'll find that you 'rediscover' rocks you'd forgotten about, forgotten what the were, or never really knew in the first place.

So, this month I'm blogging about identifying those mysterious treasures. Here's mine
While it may be fun to just hold it up and say, "This is Fred!" that's not exactly a scientific name and doesn't do anything to help you know how to work on it. Here are some tips and resources to identify your mineral.

DO A MOHS TEST ON IT:.  Interesting factoid: The earliest known mention of comparing the hardness of one stone vs. another was by Theophrastus in his treatise On Stones c. 300 BC. according to In 1812, Friedrich Mohs, a German geologist and minerologist developed the scale used by rockhounds and many others today. This is a very helpful diagram from the National Park Service that shows a way to do rough testing by scratching with common objects.


The shape of the crystals helps identify your specimen. As a rockhound, I've found that remembering cubes are isometric and pyrite is gray cubes, makes identifying it by the crystal or the formation of crystals much easier.
There are six crystal systems. All minerals form crystals in one of these six systems. Although you may have seen more than six shapes of crystals, they’re all variations of one of these six habits. Each system is defined by a combination of three factors:
  • How many axes it has.
  • The lengths of the axes.
  • The angles at which the axes meet.
If you get a chance to visit the Lyman Museum in The Lyman Museum in Hilo, HI, do it just for the crystals.  It is one of the few museums in the world that displays its mineral collection by the Crystal System rather than by the mineral type.

While the crystal system is easily understood, describing all the aspects of it takes a bit of space. If you want to learn about them, I found the explanation at the Gem Society is excellent. Check it out at HERE


 If you want to discover what your mineral is on your own, try Identification Process HERE 
This is an amazing page designed to help teachers learn the process so they can teach their students. It has excellent, simple instructions and lovely pictures for every step.


Some years ago, I purchase a dark green specimen of undermined origin at an estate sale.  It is a dark gray/green color and the crystals look like columns. (See Fred at top of blog) Some of the columns were quite thin, making me think of mica,  but they weren't flaky like mica. I decided to use the process I referred to in the paragraph above.  Here's what I found:

Color: Dark Green/Gray
Luster: Vitreous-Silky
Mohs Hardness: About 6
Streak: Colorless
Specific Gravity: I skipped this step and figured I'd go back and do it if the other tests did not get a result.

 When I had the information, I clicked through to a page they link to in order to see what I had. They came up with fifteen minerals, and rather than make the mess going back and getting specific gravity, I clicked on the first mineral on the list: Actinolite. This mineral is a combination of basic calcium, magnesium and iron silicate.

That linked to a page with a rock that looked just like mine! BINGO! It also gave me tons of information about my rock. The most important was that it contains asbestos. So if I decide I want to work on it, I'd better be sure to wear a good mask!

If you have access to Facebook, check out Rock Identification You don't have to be a member to see it, but if you want to have your rock identified, you need to join the over 42,000 rockhounds who are already members.  This is not a sales board, there are others for that. However, that nifty rock your grandfather gave you when you were a kid may just turn out to be something interesting!

I had one rock that I tried the Identification Process on and couldn't come up with a good answer. I had figured it was about 8 on the Mohs scale, but the drill point I used may not have been what I thought it was. I went to the Facebook group. After some back-and-forth among the group, it was decided that it was Quartzite. (Mohs 7).



There are two books I go to again and again, sometimes to help with identification, and sometimes because they are so darn pretty!

GEMS, CRYSTALS, & MINERALS by Anna S. Sofianides and George E.Harlow (Simon and Schuster) says it is "A comprehensive illustrated guide to the history, lore, and properties of these natural formations." This book is the closest thing to rock porn I can imagine.

GEODES: NATURE'S TREASURES by Brad L. Cross and June Culp Zeitner, (Gem Guides Book Company, Upland, CA)  If you're like me, you've picked up geodes from more places than you can remember, and cherished every one. This book has everything you could ever want to know about Geodes and beautiful full-color images. This is where I learned that the inclusion in one of my geodes that I thought was iron, was actually sphalerite.

Now is a great time to check out the mystery minerals in your shop. Work with the resources I've outlined above and let me know how it goes for you!

See you again on June 5!

Your Lapidary Whisperer,



Sunday, April 5, 2020

The Uncommon Beauty of Common Opal

Pendant of Precious Opal

Before I became a rockhound, I thought that opal was the flashy stone often found in rings and earrings.That type is called precious opal.  I love it, but as a lapidary I find it terribly expensive and that makes me nervous to work on it.

For lapidary purposes, I personally prefer common opal. It comes in an amazing range of colors (Colorless, white, yellow, red, orange, green, brown, black,  and blue) and patterns, making it a great material for my lapidary fun. I've even used it in two of my lapidary meal displays!

The Opal Fish slab shown with veggies

The first part was a hunk of white, banded common opal that looked for all the world to me like a slab of cooked halibut. That led me to create my first meal case I show at lapidary club shows and a county fair. Notice how the natural lines in the opal help give it that "fishy" look!

Green Opal Pickle Relish

The second was a chunk of green opal that made me think of hamburger pickle slices. I'd just started working on a hamburger meal at the time and I blythely put it into a saw to slice without examining it closely. This was the moment I learned about how easily common opal
can fall apart. The sound it made when it exploded in the closed saw was amazing.  Stopping the saw and opening the top, I was treated to a view of thousands of small bits of green opal everywhere in the saw, including the oil. Once it was cleaned up, I decided the bits looked a little like pickle relish. So I added a few small shards of red glass, and my repurposed opal was ready.


Australian Dendritic Opal

The range of common opal that is suitable for cabochons is almost limitless. The solid colors are beautiful, but since opal tends to take more of a lustre than a shine, opal with dendrites and other inclusions makes a cab with a story to tell.

In my shop, I like to work with this material. At between 5.5 and 6.5 on the Mohs Scale, it works fairly quickly, but is hard enough to hold up a bit and not disappear under the wheel.  Like I said above, the finishes aren't shiny, more of a luster. The dendritic  "kite" shows a shine at the center because the light was right over it there.

Here's a lovely piece of Blue Opal I'm looking forward to working on. It has a few gold-colored imperfections, but to me,they help tell the story.


Because common opal is amorphous (lacking a natural shape, not crystalline: perhaps a geletain
mineral), it is classed as a mineraloid. It also contains water that can range from 3 to 21 percent of its weight. It occurs in fissures of other rocks, giving it its shapes. That moisture level is why some dry out and crack. If you've purchased some opal at a show and it is in a container with water, it's probably best to keep it that way or it may craze, fracture, or lose its color.

Boulder Opal from Australia

I chose this boulder opal, not because of the precious flashes--it doesn't have any--but because the clarity of the opal shows how the bits of debris settled at the bottom when the opal was still a gelatin. If you can enlarge this image on your screen, you'll see what I mean.


Especially when I'm at shows, I tend to find opal specimens that are just incredible to look at, and I'd never want to cab.  This limb-cast is from the Blue Forest in Eden Valley, WY--which was a forest once, eons ago, but is desolate now.

Blue Forest Opal

Please send your comments about common opal to

Be sure to visit my next blog post on May 5.  It's all about ROCK'N RESOURCES FOR TODAY! You'll love it!

Your Lapidary Whisperer

Thursday, March 5, 2020


Cabochon with Azurite
You know how some of the minerals we use to create cabochons contain metals as an integral part of their makeup, like Azurite Cu₂, and Malachite Cu₂CO₃ (OH)₂.in which copper is part of their chemical makeup. Yet there are times when a metal is side-by-side with a mineral in a slab and that situation allows you to make some unique cabs.

My experiences in working with materials that contain metal is all over the board.  For example, the Azurite above has a hardness Mohs rating of 3.4 to 5 and Copper comes in at 3. However, if the material is in matrix, the harness of the matrix must also be taken into consideration.  With the mixes pictured below including the copper and epidote are wildly different with the epidote coming in at 6-7 on the hardness scale making it very difficult to avoid undercutting and creating a very difficult situation when it comes to polishing.
Scientifically, when you get a slab that has metals and minerals, here's what you're dealing with:

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.
Here are a few mineral/metal combinations (and not-exactly rocks) you'll probably deal with in your cab shop:

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.
Copper and Epidote
 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 & Iron Oxide
However, this Tiger Iron cab? Not exactly. 
Tiger Iron

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

Pyrite in Quartz
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.

Tin Oxide in Quartz

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, 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.

Until next time,

Your Lapidary Whisperer,


Wednesday, February 5, 2020

Chrysoprase and Little Green Apples

My Chrysoprase

The apple-green color caught my eye and the brown threads going through it impressed me.  It was being sold by the gram, which normally is a no-no for me, but I couldn't resist.  The seller had a few sample cabs of the material and they were story-worthy and very shiny!  So he got to play with my credit card for a minute and I got to take home a chunk of the talkative Chrysoprase! 
Bing Image  Gemmy Chrysoprase

Before I saw this, when I've thought of Chrysoprase,  I've thought of the gemmy variety. Chemically, Chrysoprase is a cryptocrystalline chalcedony  that contains nickel giving it its green color in a variety of shades.

It can often be found at serpentine deposits.

Depending on where it is mined, it can also be called  Australian Jade, Chrysophrase or Jadine.


Bing Image  Chrome Chalcedony

While the color in this mineral is from nickel, there are other green rocks and minerals that get their green from copper, iron, chromium, or manganese. Sometimes, chrysoprase is confused with Chrome Chalcedony which is colored by chromium.

Back to chrysoprase.  The best place for me to find it is at rock shows 😏  It comes to them from mines in California, Brazil Indonesia, Western Australia, and north-central Europe. 


Working the material was a dream.  A good dream (yes, we all know rocks that have turned out to be nightmares - I'm talking to you apatite). To me, this looks like a powerful need plants have to grow up from their roots to freedom.

At between six and seven on the Mohs scale, chrysoprase is a firm rock, and I start it on the 80 grit wheel to do the rough shaping so it doesn't take forever. The next two wheels get the shape smooth and it's ready to polish.  Since it is a fairly hard rock, I take my time on the three polish wheels to be sure I get the best result.  On my Genie, I have a 50,000 wheel that gives a glass-like polish. The cabochon above actually is a combination of gemmy (the dark green which doesn't show it here, but is translucent) and not-so-gemmy chrysoprase.

Chrysoprase from Western Australia

As you can see, the material I purchased (at the top), It has random brown lines through it, making me wonder what stories were lurking behind them. I forgot to ask the vendor where it came from, but seeing this picture of the mineral from the Yerilla Chrysoprase Mine in Western Australia, I suspect it may have come from there

All this has gotten me thinking about other gemstones that may not be all that gemmy.  Check in next month to see what I learned about "gemstones" that are better on the grinding machine than the faceting machine.

Have a comment and don't want to sign into the server I post this blog on?  Contact me directly at

Until next time,

Your Lapidary Whisperer




Sunday, January 5, 2020

Aloha! Hawaiian Treats!

I just got back from spending Christmas week in Hawaii and was once again amazed by the rock formations and lush landscaping I saw there!

This is me six years ago holding up the side of a lava tube at the Thurston Lava Tube also called the Nahuku in Volcanoes National Park on the Big Island.  I'd been hoping to do it again, but I was told that you can't do that lava tube anymore, it's under the recent lava flows. It is a reminder to all of us not to wait to get out and see the natural wonders of our planet. They may seem like they'll be there forever, but changes are always happening--and we never know where or when.

When I was in Hilo, I visited the Lyman Museum (look for a review of it in an upcoming Rock & Gem). Not surprisingly, it features some volcanic materials.

The museum displayed “volcanic bombs” from eruptions. These are composed of basalt. When the liquid is shot into the air, it comes together, twists around, and falls to earth. The shape tends to be oval, like a football. The bomb may be solid or hollow and they are collected as oddities for their shapes and textures.

Volcanic Bomb at Lyman Museum
Pele's Hair from Lyman Museum
Volcanic bombs and small sharp black splinters are not the only interesting form that falls from the eruptions. There is also Pele’s Hair, Pele’s tears, and spatter. The hair is formed when lava is flying through the air and it stretches because it’s still molten. The resulting thin strands are glass and they sometimes have a droplet at the end. Some call those droplets Pele’s Tears. Frankly, Pele's Hair looks a bit like the hair I take out of my hairbrush; silvery gray with a touch of brown.

Another formation that is called Pele’s Tears is the peridot crystals that can form in olivine. The spatter is exactly what it sounds like, bits of lava that fall to the ground.

Olivine with a few Peridot crystals
The Hawaiian Islands are fascinating for many reasons, especially the chance to see geology in action! It does have some minerals that lapidary artists and mineral collectors look for, but they are largely in microscopic amounts of labradorite, feldspar and plagioclase. The one you’re most likely to find is olivine. Olivine is a green mineral that has very little silica and a lot of magnesium and iron. It is the least stable mineral on the earth’s surface; when olivine gets weathered, it pseudomorphs into iddingsite.  While olivine is a mineral because it has an identifiable crystalline structure, iddingsite passes through many phases of change and so it is referred to as a rock, not a mineral. When the olivine is mixed with pyroxene, it becomes peridot.

Lapidaries have been known to work with basalt when it is dense enough. It will be black and probably have visible dots of other minerals in it and take a nice shine. Because basalt can be light and fluffy as Scoria and goes on a scale to very dense, it doesn’t have a Mohs scale number.  

Full disclosure: Some of the information in this blog post appeared earlier in an article I wrote for  Rock & Gem Magazine. I took the pictures of the Volcanic Bomb and Pele's Hair at the Lyman Museum where I took a whole lot of pictures for the upcoming R&G article.

Show Season is in full swing now. Don't miss the chance to see and acquire amazing specimens, slabs, and rough!  Send me a picture of your favorite!

Until next time, Your Lapidary Whisperer,