mineraloids

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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)

EDIT, 9/4/2014:  Finally fucking got it to be transparent.

Crystal Card of the Day: Amber, “I release my past and my future is healed.”

A powerful yet gentle healer and cleanser, Amber draws out and transmutes negative energy of all kinds on all levels. Amber aids in physical self-healing, emotional healing of depression, and environmental clearing. Amber opens and cleanses all of the Chakras.

Highly protective, Amber also aids in the manifestation of ideas to reality. The life force trapped within Amber promotes fertility, and its protective and environmental clearing properties make it a good stone to use to prepare a healing or birthing room. Use Amber with the Solar Plexus Chakra to increase confidence, mental clarity, and creative self-expression.

You can always use the code HCTUMBLR10 to receive 10% off your order. :D

<3 Robin

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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 asked:

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.

Don’t let obsidian steal your heart!

While this is very unlikely in today’s culture, it was almost a certainty for those individuals sacrificed by the Aztecs during religious rituals. Probably the only consolation for someone who is about to have their heart ripped out is the knowledge that the knife would be sharp. Aztec ceremonial knives were composed of flint or obsidian blades, and it is the geological properties of these rocks that would have at least made your demise swift.

The Aztecs had a reputation for carrying out horrific human sacrifices including skinning, dismemberment and decapitation and this was due to their belief that it would bring prosperity to mankind. These sacrifices were to repay the gods for the sacrifices they had made to create the Earth and Sun. This originated as the story of Cipactli, a giant reptilian being that was ripped apart by the gods Tezcatlipoca and Quetzalcoatl to create the Earth and everything on it. To appease the spirit of the monster they had just butchered, the gods promised to provide her with blood and human hearts and the Aztecs kindly obliged.

But why did they use obsidian? Obsidian has a similar composition to granite and rhyolite although it is predominantly black in appearance. This can be due to the presence of trace elements but also due to the rock being almost opaque. This is attributed to the fact that obsidian is a type of volcanic glass, formed from the supercooling of lava as its hits the Earth’s surface. The rock cools so quickly that atoms are unable to arrange themselves in a crystalline structure, preventing any visible crystals from forming.

Like quartz, obsidian displays conchoidal (scallop shell shaped) fractures and it is these that have determined its use as a cutting tool. These fractures often have very sharp edges and when you consider that obsidian has a hardness of 5.5 on the Moh’s Scale (hard enough to cut through flesh but soft enough to carve) you can start to see how it became the Aztec weapon of choice.

In fact obsidian is used in surgery today for the exact same properties. This is because obsidian can produce a cutting edge thinner and sharper than even the best steel and therefore is used on surgical scalpels for precise operations.

So, want to get your hands on some of this amazing mineraloid? Well you will have to travel to an area of recent volcanic activity as obsidian is unstable at the Earth’s surface and is easily destroyed or altered by weathering and other processes. However, it is found in many locations worldwide so if you do want a piece for your collection I’m sure it won’t be too tricky to find!

- Watson 

Image Credit: Image Kid - imgkid.com
Further Reading: http://anthropology.msu.edu/anp264-ss13/2013/04/25/aztec-human-sacrifice/
http://www.ancient.eu/Aztec_Sacrifice/
References: http://geology.com/rocks/obsidian.shtml