Gem Profile March 23: Quartz with Inclusions, Part 2
by Dale "Cougar" Armstrong, Wire-Sculpture.com
Daily Wire Jewelry Making Tip for
March 23, 2012
Included Quartz Part 2, one in a Series on Quartz
Tourmalated quartz, or tourmalinated quartz, is what we call quartz that has included tourmaline crystals. Although found naturally in a wide variety of colors (a future gem profile subject) the tourmaline crystals most often suspended in quartz are in shades of green or opaque black (aka schorl). Sometimes forming in radial fans and often singular, elongated tourmaline crystals have 6 sides (like a pencil) and can be included in several different rocks. Also known as Green Hair Quartz, Fleches d’Amour (Love Arrows) or Cupid’s Darts, water clear quartz with included tourmaline crystals is often faceted or cut into a variety of shapes and makes awesome jewelry designs. Please be aware that the stone prehnite can be confused with tourmalated quartz.
A very cool type of included quartz is called "Medusa" quartz, named for resembling the shape of the medusas rondeau jellyfish. Trapped blobs of gilalite (named for Gila County, Arizona) seem to float in the water clear quartz as seen in these Google images.
Have you seen clear quartz that looks as though a snowflake, branch or leaf has been suspended inside? This type of included quartz is known as dendritic quartz. No, the images within the quartz aren’t fossils, rather they are dendrite (meaning tree) crystal forms of either chlorite or iron oxides. Instead of trying to rewrite what has already been well written, for those of you who are interested in learning more about dendrites I suggest reading the following pdf download: How Do Dendrites Form?
Probably my personal favorite type of included quartz for jewelry design is what can be called Garden, Undersea Reef, Scenic, Monet, Lodolite, Lodalite or Dream Stone quartz. Once again, I was fortunate to have purchased quite a bit of this material many years ago, before it really "had" a name and became such a popular jewelry making item!
The latest label for this exotically included quartz, lodolite/lodalite, translates into "stone from mud" because the quartz crystals often formed in clay/mud pockets. While the silica/quartz was forming, an additional mineral became involved. These heavier materials of cookeite/chlorite settled to the bottom of the quartz formation in colors including white, beige, yellow, orange, green, light blue, light brown and light pink. Sometimes the chlorite minerals settled down and formed their known crystal shapes of rosettes, balls and radiating spheres, and sometimes the deposit became frozen during formation, appearing as clouds. (I do need to mention that occasionally the green can appear mossy, but included macrocrystalline quartz should not be confused with cryptocrystalline moss agate, that will be covered in my future cryptocrystalline articles in this quartz series.) Other materials within lodolite quartz include iron and calcite. Note though, when this quartz contains mainly bright orange iron oxides mixed with cream and white calcite, it can be labeled "Leolite." Whatever you decide to call it, in my opinion, chlorite included quartz is fabulous!
Okay, now what do you suppose happens when a quartz crystal stopped growing and another mineral crystallized on top of it, coating the original crystal with thousands of tiny colored crystals; and then additional silica entered the same vug/cavity and another quartz crystal form grew over the entire combination? Appearing as one or more ghost-like crystals within a single specimen, these are called phantoms. Otherworldly and rare, phantom crystals can be composed of a wide variety of materials including: sand, clay, chlorite, actinolite and mica or iron materials such as goethite and hematite. One other way that a phantom may have occurred could be due to temperature changes during the crystal’s formation, where severe temperature changes interfered with the original growth for a bit (like a few thousand or millions of years) and when it restabilized the crystal continued to grow in its normal manner. Phantoms are most often found in rock crystal, occasionally in amethyst or smoky quartz. Although some lapidaries will cut and polish huge phantom specimens into items like crystal balls, eggs and spheres, most examples are smaller and will make fine pendants using a wire technique such as the Caged Crystal, which will not harm the specimen in any way.
Believe it or not, almost all quartz crystals have liquid or “enhydro” inclusions. The most common is water, which appears as microscopic bubbles causing clouds or a milky look. Of course I would love to have a specimen in my collection, showing a large liquid inclusion as a bubble with fluid that moved when the rock was turned, however…it is on my wish list.
Yes, geologically speaking there are many other items that can be found included in macrocrystalline quartz, however it is my opinion that they are not pertinent to making wire jewelry, so this concludes inclusions. Next week I will finish the macrocrystalline quartz subject, after which we will move on to those items in the cryptocrystalline quartz category.
- Mineralogical Record, vol. 24, no.4. pp 311-313. "Solid Inclusions". W.A. Henderson Jr. & M.H. Weber (1993)
- The Peterson Field Guide to Rocks and Minerals by Frederick H. Pough, ISBN 0-395-24049-2
- Simon & Schuster’s Guide to Gems and Precious Stones by Curzio Cipriani and Alessandro Borelli, ISBN 0-671-60430-9
Gem Profile by Dale "Cougar" Armstrong