Everybody wants a rock...

Falling behind on the rock side of things

Uranium
Originally uploaded by thomasina.

Uranium, Nevada

Looking for a suitable rock to wind a piece of string around, I finally unpacked the rest of my mineral collection, things I hadn't seen in about three years. Hi, minerals!

This piece of "uranium" is the first rock I ever purchased, from when I was very young. I was excited not by any mineral characteristics, but because it was (at least in theory) radioactive.

Quartz on Elbaite (Tourmaline)

Quartz on Elbaite
Originally uploaded by thomasina.

Quartz on Elbaite
Santa Rosa Mine
Itambacuri
Minas Gerais
Brazil

Of course this falls into the "cute composition" category, rather than rarities or location. One of my original weaknesses was for tourmaline; I did not have the resources to purchase the nice pieces, and when I did I decided that it was too gemmy and not varied enough. I do have a nice "patriotic" from this period (vs. watermelon) that is blue, pink, and white; double keystone from Tucson.

Star Quartz

Star Quartz
Originally uploaded by thomasina.

Quartz with Hollandite Inclusions
Ambositra
Madagascar

A crystal with very cute inclusions, off of an eBay store; I am a repeat customer. They have a nice stock, though it is at the very upper end of what I expect to pay, especially sight-unseen.

Quartz, Japan Law Twin

Quartz, Japanese Law Twin
Originally uploaded by thomasina.

Quartz, Japanese Law Twin
Pampa Blanca Mine
Inca Dept.
Peru

The fine druse, likely a metallic oxide like manganese oxide, highlights the face of the Japan Law Twin (flattened, twinned quartz crystal) and provides added interest to the piece. Dana, father of mineralogy, describes them as "tabular appearing twins." Thanks to the quality and quantity of twinned crystals, we now have a much more managable name.

One of my summer interns was one of a set of identical twins, with his "better half" stationed in Japan. He gifted his brother with a Japanese Law Twin, which I think is wonderfully geeky!

Anatase close-up

Anatase close-up
Originally uploaded by thomasina.

Anatase on Quartz

Anatase on Quartz
Originally uploaded by thomasina.

Natskorhae
Hordaland Fylke
Norway

This does not show with the backlighting, but the tip of the quartz crystal is smoky. Anatase is the rarest polymorph of TiO2, titanium oxide (rutile and then brookite are the most common) and forms lovely tetragonal dipyramids often found in association with quarz.

Potassium feldspar altering to epidote and albite

Potassium feldspar altering to epidote and albite
Originally uploaded by thomasina.

Potassium feldspar (pink) altering to epidote (green) with albite (white) alteration rind.

Self-collected
Yerington, Nevada, USA
1994

Quartz, Elbaite, Pyrolusite

Quartz, Elbaite, Pyrolusite
Originally uploaded by thomasina.

A nice composition, with a water-clear quartz crystal.

Aricanga Mine
Sao Jose da Safira
Minas Gerais
Brazil

Blue Phantom Mine

Blue Phantom Mine
Originally uploaded by thomasina.

Blue phantom caused by fine-grained black shale particles (the fine grains scatter light waves on the short-wavelength blue end of the spectrum, producing a blue effect -- same as in our sky). Also, milky quartz, caused by fluid inclusions. Overall, a pleasing yin-yang effect. Bought off of eBay from the collector.

Phantom Quartz
Blue Phantom Mine
Mt. Ida, Arkansas

Collected by Eric Greene

Closeup of quartz crystal with specular hematite phantom

Closeup of quartz crystal with specular hematite phantom
Originally uploaded by thomasina.