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18 Various Kinds of Opals  

When most people think of an opal, they might think of a milky-colored stone containing a rainbow of stripes or flecks inside it.  What many people don’t know is that they are incredibly diverse in appearance, and are not actually minerals.  Opals are a solid, amorphous form of silica, and are classified as “mineraloids”.  Like other mineraloids, such as amber, pearl, and obsidian, they lack structural order, or “crystallinity”. 

From the top:

  • Black Opals
  • Cat’s Eye Opals
  • Dendritic Opals
  • Flamingo Opals
  • Peruvian Pink Opals
  • Zebra Opals
  • Leopard Opals
  • Yowah Nut and Koroit Opals (both have the same characteristics - they merely come from two different areas).
  • Brown Opals
  • Ethiopian Honeycomb Opals
  • Green Opals (Serbian, Tanzanian, and Brazilian)
  • Peruvian Blue Opals
  • Matrix Opals
  • Landscape Opals (Andean and Australian)
  • Mexican Fire Opals
  • Crystal Opals
  • Australian Boulder Opals
  • Ethiopian Ribbon Opals

(Side note - the image backgrounds are transparent, except for the matrix/landscape picture, which seems hellbent on being an asshat, no matter how many times I try to fix it)

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Been busy with finally building up the garden that we’ve been planning since moving here, so I’ve been neglecting this blog a little more than I like. But to make up for it, here’s a pretty little opal for you all. I feel like this exemplifies what I love about opals. Gorgeous little iridescent veins.

overfedvenison said:

What's the weird meatlike thing in the box with your SNES?

Oh, you’re probably referring to one of the two rocks that were in the box.

image

I’ve had them since someone gave them to me in fifth grade (so, roughly 20 years, meaning that these rocks are older than a lot of the people on tumblr).

I believe the red one might be a chunk of red obsidian, but I can’t be certain.  I have no idea what the other one is.

Opal is an amazing stone both magically and mineralogically. Since it doesn’t have a crystalline structure, it is not classified as a mineral but a mineraloid. Opal is amorphous and made of hydrous silicon dioxide and can contain up to 21% water, though it usually contains 6%-10%. It is found in fissures of rock, usually limonite, sandstone, rhyolite and basalt. 97% of the world’s supply of opal comes from Australia.

Because of opal’s unique nature, individual opals can vary widely in appearance from one another. Opals come in a variety of colors and many display flashes of other colors within as well. Types of opals may be named for their color, the play of colors within, the location of their origin, or the other minerals they accompany.

Precious opals display a play of color caused by tiny silica spheres arranged in a network. As the light passes through the spheres it is diffracted like a prism and displays different colors based on the arrangement of the spheres. As the angle of the light source in relation to the stone moves, it creates brilliant flashes of changing color.

Common opal, also known as “potch” does not display this effect because the spheres within are not arranged in a manner that promotes this play of color, but all opals have opalescence, a pearly luster. While common opal isn’t as flashy as precious opal, it can also be a gorgeous stone and is useful for jewelry and magick.

Fire Opal is the name given to opals that display “firey” colors such as red, orange and yellow. These may be transparent or translucent and they do not show to play of color found in precious opal.

Boulder Opal is a rock of another type, the “host rock”, with opal within it. Since opal forms in fissures in rocks, this is common and can be very lovely. Magically, the energy of the host rock can be amplified by the presence of the opal. The opal inside boulder opal can be of any sort.

Black Opal is any dark colored opal. This includes dark blue.

Opal Correspondences and Lore

Black opal is associated with Scorpio.
White opal is associated with the Moon.

Opal is the birthstone for the month of October.
It is a traditional gift for the 13th wedding anniversary.
Opal is the national gemstone of Australia.
Black Fire Opal is the state stone of Nevada.
Most opals will fluoresce under a UV light. Synthetic opals will not.

Opal for Magick

Opal contains the energy of all the elements and can be used for just about any magical application. It also amplifies the energy of anything it is used with and can amplify the energy of the wearer. However, opal can be unpredictable and should be used with a bit of caution.

Opal set in gold and worn on the right index finger makes a good talisman for those who must work with other people. It enhances foresight, empathy and confidence and helps the wearer influence people to his point of view.

Opal is said to aid in invisibility spells and can be used as a talisman to help your actions go unnoticed.

Fire opal is said to help protect from injury from natural disasters.

Any opal can be used as a scrying stone and to enhance psychic abilities, to increase intuition and inspiration and to help recall past lives.

It is said that opal is a very good stone to wear for general luck, especially for those born in the month of October. Opal is a stone of inspiration, imagination and emotion and may prove valuable to writer’s, musicians and artists. However, opal can magnify emotions and mirror the emotions of others and can help break down inhibitions. Therefore, it may not be the best stone to wear on a regular basis.

Caring for Your Opal

Opal is a very soft and sensitive stone. Because of its high water content, it is subject to damage by extremes of temperature and can be easily chipped or scratched. Some recommend storing opal in water when not in use.

Lovely Listwaenite!

Listwaenite, in this case, is the alteration product of an already altered ultramafic rock. 
The definition of listwaenite has evolved so much through the last decades that it is best understandable as a concept rather than a proper mineral or mineraloid or mix of minerals (such as quartz with carbonates and sericites, but sometimes other minerals and sometimes not even with quartz… it is, indeed, an evolving term!)

This particular rock, starting out as a harzburgite peridotite (a rock made of mostly olivine and some orthopyroxene with a smattering of chromite) born in the earth’s mantle, was altered to serpentine en route to its present position at an altitude of 2000m in the mountains of the Pindos. Serpentinization is essentially a process of hydration of these ultramafic rocks and wherever hydration occurs, there are plenty of fluids around to circulate and cause further alteration of whatever has been altered before. These processes have the wonderful tendency to aid the escape of elements that do not easily fit into the atomic structures of the minerals in the original rocks; the fluids accompanying alteration transport these fugitive elements, redepositing them within brittle fractures as veins when the fluids cool or run out of steam, so to speak.

In the case of listwaenite, these fugitive elements can even be big fat atoms of gold. Gold is so rare within mantle rocks that we do not even bother to analyze for it. But these alteration processes are so highly efficient in concentrating such rare ungainly elements that economic concentrations of gold can be found with listwaenites. 

The colors of listwaenite vary as much as its definitions: red and yellow is popular; yellow and green is mentioned in the literature frequently, and semi-precious varieties are light grey and ethereal in appearance. In the gold rush country of California, prospectors are said to have called it “blue jay.” But my favorite color is this teal blue sample!

-AR

Photo by – AR.

http://www.empr.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/BulletinInformation/BulletinsAfter1940/Documents/Bull108_app_I.pdf

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