Agate Cabochons

Day 174: Many of the types of agate shown in this image are no longer available as rough, mined out of the locations in which they were found. I was fortunate that my interest in rockhounding occurred when rock shops were common and the materials were readily available. By the time I moved here over thirty years ago, I was ready to retire from cabochon cutting, and sold my saws and grinding machinery, as well as several dozen crates of rock. I kept my mineral collection and the stones I'd cut, but they've seldom seen the light of day in the intervening years. Most of the minerals have lost their labels, but I had it for this Riker-mount display. The cabochons are all 20mm x 30mm, and include the following:

Row 1: Blue Lace, Scenic, Royal Blue, Crazy Lace, Cathedral, Tree, Montana;
Row 2: Sunset, Calico, Graveyard Point Plume, Flame, Purple Lace, Green Moss, Carnelian;
Row 3: India Moss, Buckskin, Tube, Sagenite, Anderson Dam, Seafoam Chrysoprase, Fortification;
Row 4: Parrot-wing, Chalcedony, Utah, Sunset, Mount Rainier Plume, Yellow Moss, Citron Chrysoprase;
Row 5: Dendritic, Carnelian, Horse Heaven Moss, Banded, Laguna, Arizona Flower, Powell Butte.

Diaspore

Day 296: From the time I was a very young kid, I enjoyed collecting rocks. My interest was piqued further when one day on my way to school, I picked up an egg-shaped lump and threw it against a handy boulder where it broke apart to reveal crystals and a radiating round white mass similar to the green ones shown here. At 8 or 9 years old, I was convinced I'd found a fossil mushroom and, to this day, I'm not sure what it really was, but it occupied a place of honour on my dresser alongside a geode, a 3-inch quartz crystal and a 1-inch diameter garnet as well as other less intriguing specimens. As an adult, I kept a mineral collection in various display cases, and I dabbled in cutting cabochons from agate and other semi-precious stones. During a dayhike, I happened to find this conglomerate lump in an unlikely location and rather than forget to pick it up on the way back, I tucked it into my pack and carted it around all day. On arriving home, I tried to identify the green mineral but was unable to determine much about it other than its hardness (near 7 on the Mohs scale). Years later, I asked a visiting geologist for his expert opinion. He was reluctant to commit without testing, so I allowed him to chip off a bit to take back to his lab. A few weeks later, the diagnosis came in: diaspore, an aluminum hydroxide oxide which occurs only very rarely in gemstone quality (obviously, this specimen is not gem grade). I was very grateful to finally have a label to put on it, and it remains one of the best finds of my rockhounding career.

Agates From Around The World

Day 102: While my husband and I were both rockhounds, his interest was primarily in faceting and lost-wax casting while I leaned more toward the traditional cabochon-cutting and mineral collecting. We both exhibited at gem shows locally, and frequently gave demonstrations in the art of turning rough rock into finished stones. For display purposes, I created a series of 20 x 30 mm. cabochons of agates from sources around the world. Many of these stones came from locations in Washington; some were ones we collected ourselves. Others represent global sources which have now dried up, and good examples of raw materials such as Parrot-wing and Laguna are now very difficult to find.

For the curious among you, I'll post the varieties shown here.
Top row: Blue lace, Scenic, Royal blue, Crazy lace, Cathedral, Tree, Montana
Row 2: Sunset (v. 1), Calico, Graveyard Point plume (backed), Flame, Purple lace, Green moss, Carnelian
Row 3: India moss, Buckskin, Tube, Sagenite, Anderson Dam, Sea-foam chrysoprase, Fortification
Row 4: Parrot-wing, Chalcedony, Utah, Sunset (v. 2), Mount Rainier plume, Yellow moss, Citron chrysoprase
Row 5: Dendritic, Carnelian, Horse Heaven, Banded with pyrite inclusions, Laguna, Arizona flower, Powell Butte moss

Stibnite

Day 101: This is a long walk from the realm of Botany, but I've had another relapse and am getting desperate for bloggable material. That said, I've been interested in other sciences off and on since I was a very small child, and geology/mineralogy filled much of my teenage years. I was forever bringing home pocketsful of rocks (an improvement on tent caterpillars, I suppose), and over the course of time, found a number of examples of unusual native materials including several zeolites. However, true to my nature as a Crow, I longed after other shiny objects, and by the time I was in my early 20s, I'd begun a collection of quality thumbnail specimens. A rockhounding friend had an enormous museum-grade stibnite cluster over which I drooled every time I was in her shop. Eventually, I found a stibnite I could afford (according to the price tag, it cost me all of $5). It has remained one of my most prized specimens despite competition from more brightly coloured and showier pieces. It came from Czechoslovakia. Stibnite is a relatively soft (2.0 Mohs) metallic sulfide (Sb₂S₃) and occurs in long prismatic crystals.

December Blues

Day 71: If you were born in the month of December, you are more fortunate than most when it comes to a selection of birthstones. There are three choices: blue zircon (if your taste runs to faceted stones), turquoise (for a more earthy look) and the classic elegance of lapis lazuli.

I bring this up because a friend just asked me if I could verify that a piece she owns is in fact lapis. I have not seen it yet, but I did advise her that there are a number of imitators (most notably, dyed howlite), but all lack the telltale flecks of pyrite which distinguish much true lapis. Lapis aficionados will argue whether or not pyrite is desirable and to my way of thinking, it's a matter of personal preference. I like it. On the other hand, the stonecutter is more likely to say that good lapis excludes pyrite because it makes it more difficult to grind and polish due to undercutting of the softer material.

I sold my rockhounding gear years ago after deciding that creating cabochons such as these was not worth the hours spent with wet, cold hands, but I kept much of my more valuable rough including a stash of genuine lapis. In any event, I seldom wear jewelry and get more pleasure from seeing the raw minerals in my collection.

Lovely Lapis Lazuli

Day 353: My interest in rocks began at a very early age, and by the time I was nine years old, I had a mineral collection which (to my mother's dismay) covered the top of my dresser. Each specimen was labelled with what I believed it to be (often erroneously) and where I had found it. As I grew to be an adult, I developed an interest in stone-cutting as an adjunct to rockhounding, and was not content to work simply with slabs of agate or pieces of Australian opal. One of my favourite stones was lapis lazuli.

Lapis is somewhat difficult to work. Pyrite inclusions are desirable; veins of quartz are not. Both create problems for the lapidarist in that they are softer or harder than the blue matrix material. I was quite proud of the uniform finish I achieved on this particular stone (a 20 x 30 mm. cab).

Fake lapis abounds in the jewelry market. Most often, it will be blue-dyed howlite. However, although howlite also contains quartz, it never contains the pyrites which typify true lapis.

Hard Rock Mining

Day 140: By special request: rocks and a rockhounding story.

In 1972, a deposit of amethyst quartz was discovered by a farmer near Big Lake, Washington (Walker Valley, Skagit County). A few years later, my husband and I became aware of the site through a friend who ran a lapidary shop. Avid rockhounds that we were, we made several field trips, Bruce keen on finding some faceting-grade crystals while I was more interested in collecting mineral specimens for display. Although Bruce's hopes for flawless material were never realized, we did gather both clear quartz and amethyst, and also some nice calcites (the yellowish "roses"), but the "digging" was not easy. The crystal vugs were set in a very dense basalt and had to be sledgehammered and pried apart with long crowbars.

The specimens shown here all came from one of our most successful digs. It was also the most physically demanding, and blisters, nicks and slices from sharp rock edges were par for the course despite whatever protective gear we wore. During the brutal excavation of the amethyst, a fragment of basalt embedded itself in the edge of my lower lip. I didn't notice it until a few days later, and then assumed that it was just a scab. By the time I realized it was a piece of rock, it had healed over, leaving a little spot like a blackhead which I could not squeeze out. Six months or so went by, and although it didn't cause me any particular discomfort, it bothered me that it was there.

I'm not particularly squeamish unless the blood I'm seeing is my own, so when I decided to do a job of home surgery to remove the chip, I laid out my tools (Exacto knife, tweezers and a needle) on the bathroom sink and closed the lid on the throne in case I started to pass out. It was a good precaution to take, because I got light-headed several times before extracting a tiny sliver of black basalt sharp as a splinter from a razor blade's edge half an hour later.

Walker Valley is now only open to permittees (yeah, another permit), and I understand it still yields some nice specimens of amethyst and clear quartz, but I'm content with those I dug forty years ago. I still collect rocks, but only those I can easily pick up off the ground.