Latest Treasury - Featuring Rocks!

Wednesday, January 30, 2008
Here's an image of the items featured in my newest treasury (Get Your Rocks Off!!!).

Beautiful stones wouldn't you agree!

You can see it here

Stone of the Week - Moonstone

Tuesday, January 29, 2008
Moonstone is a type of feldspar called orthoclase; feldspars are a group of minerals composed of aluminum silicates, and are the most common rock forming mineral on Earth. Moonstone, as well as a number of other minerals in this group, stands out for it’s ability to diffract reflected light creating a sheen (technical term is Schiller or Adularescence). In the case of Moonstone, it is often a silver to blue color sheen that is reflected.

Schiller or Adularescence is what gives Moonstone its 'glow' or 'sheen', which is usually silver or blue.

Moonstone comes in several colors, the more common being white, gray, and peach. White Moonstone, with an especially strong bluish sheen, is often called Rainbow Moonstone, and is actually not a moonstone but another feldspar mineral called Labradorite; it is very popular to use in jewelry. The most valuable is the blue Moonstones from Sri Lanka, particularly as there are fewer being found thus driving up prices for this most beautiful of stones.

Moonstone comes in a variety of color, though the more common ones are gray, peach, and white.

Moonstone is a historically important gem, valued by royalty and commoners alike. It was very popular during the Art Nouveau, and currently is the preferred birthstone for June in several European countries. In several cultures, Moonstone is considered to be magical and have special properties. Some in India regard this stone as a ‘dream stone’, bringing good visions at night, while in some Arabic communities, women will sew these into their clothing as it is a symbol of fertility.

Rainbow Moonstone has a lovely blue sheen that is very desirable by jewelry artisans, although the name is a misnomer as its actually a type of Labradorite instead of Moonstone.

If there's a stone you would like to know more about - drop me a line! Have a mystery stone? Feel free to post a comment about it, including a link to a picture, and it could be featured on this blog!

Moonstone Facts:
Chemical composition: KAlSi3O8
Crystal System: Monoclinic
Color: Most commonly white, peach, or gray; also blue, pink, green, and brown
Habit: Prismatic, Tabular
Fracture: Irregular/Uneven, Conchoidal
Cleavage: Perfect
Luster: Vitreous
Hardness: 6
Specific Gravity: ~2.55
Streak: White
Occurrence: Worldwide

A Guide to Rocks and Fossils by B. Busbey III, R. R. Coenraads, P. Willis, and D. Roots. Published 2002 by Fog City Press. ISBN: 1877019518 – Moonstone.

Mindat – Orthoclase.

Wikipedia – Moonstone.

Stone of the Week - Obsidian

Sunday, January 20, 2008
Obsidian forms from the melting of granitic rocks deep below the earth’s surface. It cools so quickly that it cannot crystallize, and instead forms as a volcanic glass. Since it has no crystalline structure, it is considered a mineraloid rather than a true mineral. [A mineraloid is something that is mineral-like but has no crystalline structure, such as amber, opal, and obsidian]. Obsidian is also known as volcanic glass, Apache Tears, Bergmahogany, and Black Lava Glass.

Obsidian comes in a variety of colors including black, brown, reddish brown, and dark green.

While the most common obsidian is black in color, it can also be found in brown, dark green, and reddish brown varieties (sometimes called Mahogany Obsidian). Another variety, and the most valuable, is called rainbow obsidian. Rainbow obsidian contains gas bubbles which formed layers or bands in the lava; when cooled the bands of bubbles remained and can reflect light forming a sheen of rainbow colors. [Fensterdog on Etsy asked about a golden or silver sheen - this is also due to the gas bubbles reflecting light.] Sometimes the hot lava can begin to cool and the formation of crystals begins, but is cooled quickly enough they do not continue to grow, resulting in snowflake obsidian. The little white/gray patches are small crystals of a mineral called cristobalite.

Obsidian can also form two special types called Rainbow Obsidian (left), and Snowflake Obsidian (right).

Obsidian has a conchoidal fracture, which usually looks smooth and spherical, and can create very sharp edges – so sharp that obsidian has been used for hundreds of years as cutting implements. Many indigenous tribes used it for arrow points and knives, as well as for decorative uses. It was a valuable commodity and traded between Native Americans, as well as tribes on other continents. Obsidian has unique properties that can be associated with particular volcanoes, which has made it possible for archaeologist to trace where some artifacts originated from. Today obsidian is used for surgical cutting implements, and more commonly as a gemstone for jewelry.

Obsidian has been used as arrowhead points by tribes in the past, and today is commonly used in jewelry.

If there's a stone you would like to know more about - drop me a line! Have a mystery stone? Feel free to post a comment about it, including a link to a picture, and it could be featured on this blog!

Obsidian Facts:
Chemical composition: Mostly SiO2, with MgO, Fe3O4
Crystal System: na
Color: black, brown, dark green, reddish brown
Habit: massive
Fracture: Conchoidal
Cleavage: na
Luster: Vitreous
Hardness: 5-5.5
Specific Gravity: ~2.6
Streak: white
Occurrence: Obsidian can be found around the world where lava has erupted at the surface and cooled quickly. Outcrops can be found in the western US, Armenia, Turkey, Italy, Mexico, Greece, and Scotland.

A Guide to Rocks and Fossils by B. Busbey III, R. R. Coenraads, P. Willis, and D. Roots. Published 2002 by Fog City Press. ISBN: 1877019518

Mindat – Obsidian.

Wikipedia – Obsidian.

Stone Q&A - Chinese Puzzle Stone

Thursday, January 17, 2008
I recieved this question from Dharma Designs...
"I'd love to know more about Chinese Puzzle Stone. Is it white turquoise, howlite, or something all together on its own."

Personally I am not familiar with Chinese Puzzle Stone, so I had to hit the books and the web. There was surprisingly very little info out this stone - even when stones are actually imitation of other stones there's usually something out there.

However, I did find a mention that called Chinese Puzzle Stone 'White Turquoise'. Now there is actually no such thing as 'White Turquoise' - in fact it is none other than regular old Howlite (and occassionally Aluminite). Since Howlite is often dyed blue and used as an imitation of 'Turquoise', a new trend has started to call the white Howlite, 'White Turquoise', and sometimes also labeled 'White Buffalo' or 'Sacred Buffalo' Turquoise. This is simply done to make the stone appear more valuable.

On the left is regular Howlite, on the right is Howlite that has been dyed blue to imitate turquoise (ironically these are shaped as a buffalo!)

I did compare online photos of Chinese Picture Stone with Howlite, and other 'White Turquoise' stones, and they indeed look alike. Hence, my best guess is that Chinese Picture Stone is in fact Howlite. So Dharma, I hope this answers your question! If anyone who reads this knows any more about Chinese Picture Stone, please feel free to leave a comment on this blog!

Sneak Peek - This weekend's Stone of the Week blog will be about Obsidian!

Stone of the Week - Tourmaline

Saturday, January 12, 2008
While many believe that diamonds are the most valuable stones on the planet, there are several that can exceed the value, including tourmaline. Tourmaline is a complex mineral, resulting in its fabulous variety of colors. Tourmaline is divided into seven different groups based on its chemistry: schorl (black) is the most abundant, elbaite (many colors), dravite and buergerite (brown), rubellite (pink), chromdravite (green), and uvite (black, brown, and yello-green). Of all the color varities, the pink and watermelon (green & pink bands) are often the most sought after. Most gem quality tourmaline is in the elbaite group.

Tourmaline can form in a variety of colors.

One of the most interesting properties of tourmaline is that it is pleochroic – this means that it appears different colors when seen from different axes of the crystal. It also has electrical properties, and when heated can become positively and negatively charged, attracting dust particles. In fact, the word tourmaline comes from the Sinhalese word turamali, meaning “stone attracting ash”.

Tourmaline can be found as prismatic crystals in a hexagonal shape, from very large to the very small.

Tourmaline is most often associated with igneous rocks, such as granites or pegmatites, however it can be found in some metamorphic rocks. It is commonly found with other minerals such as quartz, beryl, and topaz. Tourmaline can also occur inside quartz as thin, needle-like crystals, forming what is known as tourmalinated quartz. While found all over the world, tourmaline has been found in great quantities in the USA, in particular the states of Maine and California.

Most tourmaline used in jewlry comes from the elbaite group.

Tourmaline is the birthstone for October. In metaphysical sense, tourmaline is said to dispel negative energies and enhance the mind. The black variety schorl, is said to have been used in the past to create mourning jewelry. The pink and green varieties are said to have been used as funeral gifts by some Native Americans.

If there's a stone you would like to know more about - drop me a line! Have a mystery stone? Feel free to post a comment about it, including a link to a picture, and it could be featured on this blog!

Tourmaline Facts:
Chemical composition: Varied - in general it is
Na(Mg,Fe,Li,Mn,Al)3 Al6(BO3)3 Si6O18 (OH,F)4
Crystal System: Hexagonal
Color: Varied: pink, green, brown, yellow-green, dark blue, black (most abundant)
Habit: Prismatic crystals or massive
Fracture: Uneven or subconchoidal
Cleavage: Poor, rhombohedtral
Luster: Vitreous
Hardness: 7
Specific Gravity: 3
Streak: Colorless/White
Occurrence: Worldwide

A Guide to Rocks and Fossils by B. Busbey III, R. R. Coenraads, P. Willis, and D. Roots. Published 2002 by Fog City Press. ISBN: 1877019518

Rocks, Minerals, & Fossils of the World by C. Pellant and R. Phillips. Published 1990 by Little, Brown and Co. ISBN: 0316697966

Wikipedia – Tourmaline.

Mineral ID Kits

Thursday, January 10, 2008
As a sort of followup to my recent post about Mineral ID, I've had a couple questions about Mineral ID kits. You can find several of these kits online, usually either fairly basic and cheap ($10 or under), or the more expensive deluxe kits ($50 or more). Most of the basic kits include items for testing hardness, streak, sometimes magnetism and dilute hydrochloric acid (used to test for carbonates as they will fizz). However, you could try to put one together yourself of course. What you would basically need is:

Hardness: Penny, Glass Plate, Steel Knife, Emery Cloth, and any stones you'd want to try using for testing hardness (e.g. quartz & flourite)

Streak: Porcelain plate which you can buy individually, or I've heard that some try using a heavy piece of paper

Magnetism: Something like a paperclip or nail to see if it sticks to the sample, and a magnet to see if you can feel any kind of magnetic attraction between the sample and magnet. There aren't too many minerals you'd use this on, and most are already labeled as such, hence I didn't bother to include it in the article.

Reactivity to HCl: This I didn't bother covering in the Mineral ID blog as its more for testing limestone, a rock. However if you'd like to do this, instead of HCl, some carbonate minerals will react to Vinegar as well. (While the HCl used is dilute, it can still be dangerous - its an acid after all, so be careful with it. Vinegar is a little less dangerous, but again don't do something like putting it in your eye!) Just put some in a dropper bottle or use a eye dropper, place a drop or two on your sample, and see if it fizzes - if it does it has carbonate in it, which is in things like limestone, chalk, and marble.

Fluorescence: UV light

Everything else is pretty much done simply through observing the sample with your own eyes. A magnifying glass can help you look at your samples up close.

If you'd rather buy a ready made kit there are numerous ones online - I have never purchaed one so I can't vouch for any supplier. Just google Mineral Identifcation Kit and you'll get plenty of results!

As always feel free to contact me or leave a comment if you have questions!

Mineral Identification

Monday, January 7, 2008
Do you look up information about stones but don’t always understand what some of the terms mean? Specific Gravity? Streak? Moh’s Hardness Scale???

That’s what this weeks blog will try to answer. Don’t feel bad if you don’t know/understand what these terms mean for they’re not commonly used by the layperson. Geologists developed means to describe stones as a method for identification and classification. Minerals and rocks have different means of identification; minerals by things such as color, luster, and hardness, while rocks are often classified based on mineral composition. This article will focus on mineral identification, since that is what most jewelry is made out of (there will be a later article about rocks and their identification).

One of the first ways most everyone tries to identify stones/minerals is by color. Color can help narrow it down, but cannot necessarily be the only thing relied upon for identification. Looking at the first image, you see 6 different rocks pictured. Have an idea what they may be? Do you think they’re the same, or are they all different? The answer is actually both – the 3 samples on the left side are all calcite but in different colors, the 3 on the right side are all shades of green, but are different minerals: chrysocolla (in back), malachite (middle), and prenhite (front). Also notice how the prehenite and green calcite look remarkably close in color – a great example of why color cannot always be relied upon for identification. However it can help – for instance Malachite only occurs as a green mineral.

The ability for light to pass through a mineral is known as its transparency, and minerals are divided into transparent (light can pass through easily; e.g. quartz), translucent (some light is transmissible but you can’t see through it; e.g. chalcedony), or opaque (no light can pass; e.g. malachite) minerals. This is obviously not full proof either, as many minerals do not form perfectly, and thus may appear cloudy. The three samples of calcite in the first picture are a great example; while calcite is considered to be transparent, these samples are not.

Luster is how a mineral reflects light off of its surface. Metallic minerals such as pyrite are said to have a metallic luster, while nonmetallic minerals are usually described as having a vitreous/glassy (e.g. quartz), resinous (e.g. amber), pearly (e.g. gypsum), silky (e.g. muscovite) or dull/earthy (e.g. chert) luster.

Tiger eye (left), labradorite (back), moonstone (right)

Sheen refers to the reflection of light within a mineral caused by the internal structure. Hence not all mineral exhibit the properties to create a sheen effect. The cat’s eye effect known as Chatoyancy, is an example of sheen caused by the reflection of light on fiberous minerals; Tiger eye is a perfect example of this. Star sapphires and rubies are actually exhibiting chatoyancy that is occurring in a star pattern, or asterism. Iridescence is seen in labradorite, while Adularescence is the sheen visibile in opal and moonstone.

Isn’t a common method for identification but can be used – besides that its pretty cool too! Luminescence occurs when a mineral is held under ultraviolet light and the mineral glows (fluorescence if only while under the light, phosphorescence if it continues to glow when the UV light is turned off). This does not occur in all minerals, thus it can be used to some extent for identification. Common minerals that exhibit luminescence include fluorite, calcite, and opal.

Different minerals create different streak colors. From left to right: chrysocolla, malachite, galena, specular hematite, azurite

Streak is the color a mineral is in powder form. This is usually tested by scratching it on a white porcelain streak plate. Each mineral has a unique streak color, regardless of what color it may appear as. For instance quartz comes in many colors; however it always has a white streak (i.e. you see no color on the streak plate). Some minerals may have a streak that is the same color they are (e.g. galena is silver in color and has a silver streak), while others may have a different streak color (e.g. gray hematite will streak red).

Flourite (left) is not as hard as this Rose Quartz (right).

(This is not recommended for good specimens or beads - use beads you don’t mind potentially getting scratched!) Hardness is just that – how hard a mineral is and is tested by using materials with a known hardness. The Mohs hardness scale was established with a scale ranging from 1 (softest) to 10 (hardest); each mineral has a known hardness number assigned to it. Those minerals with a higher hardness number will scratch those with a lower number.
Mohs Hardness Scale
1. Talc
2. Gypsum
3. Calcite
4. Fluorite
5. Apatite
6. Feldspar
7. Quartz
8. Topaz
9. Corundum (ruby)
10. Diamond
Items with a known hardness can be used for testing, including your fingernail (2.5), coin such as a penny (3.5), glass (5.5), steel knife (6.5), and emery cloth (8.5).

Thus in the third picture you can see a piece of fluorite on the left, and rose quartz on the right; on the glass plate behind the samples, you can see a scratch on the edge that was made with the quartz next to it, but the fluorite was also drawn against the glass plate and left no scratch. In the next picture, you can see where the Flourite was able to be scratched by a nail, yet the Quartz could not be scratched by it. Both however are hard enough to scratch the penny.

These next few are not necessarily as helpful as the first, because they would either require you breaking your rocks/beads, or require very good specimens showing these features clearly. However I have included them since they are usually mentioned in any guide that gives specific properties about different minerals.

From Left to Right: Various Quartzes (Rutilated Quartz, Double Terminated Quartz, Rose Quartz), Malachite (all three in the middle), and Calcite (all three on the right).

This refers to how the crystals form, or their shape. It can vary from small crystals to large amorphous masses. Some of the common terms to describe habit include:
Tabular – generally flat with broad faces
Reniform – generally rounded like a kidney
Fibrous – thin, thread-like prismatic crystals
Botryoidal – bumpy or like a bunch of grapes
Acicular – many needle-like crystals usually in a radiating pattern
Massive – no distinct shape
Dendritic – tree-like branching shapes
Columnar – formed like columns
Stellate – star-like formation

In the above image, Malachite in the middle shows off its most common form in the middle, botryoidal, but it can also form as acicular crystals shown at the top. Once cut and polished however, the habit is no longer determinable (bottom).

Garnet, Calcite, and Muscovite

Cleavage & Fracture
Cleavage is where bonds are weak in a mineral and break along a plane. Sometimes when a mineral is broken, it will break along these cleavage planes. Muscovite for example, has perfect cleavage along one plane; it breaks along its cleavage planes very readily and is easily seen in most specimens. Calcite has three cleavage planes, and Garnet has none.

Fracture is the pattern that sometimes results when a mineral is broken – not very usuable, though perhaps most recognized is the conchoidal fracture that Quartz or Obsidian has.

On the left is Galena, Anhydrite on the right.

Specific Gravity
Specific Gravity is the density of a mineral. A hard one to use in some respects, as you would have to calculate this out for your beads/specimen. However in some instances it can be useful – for instance when trying to tell Galena apart from another gray, metallic mineral (of which there are many!) since it is very heavy. The above picture shows two different samples approximately the same size. Yet notice that Galena weighs about twice that as the Anhydrite sample!

Crystal System
Crystal system refers to how the mineral’s internal molecular structure is arranged. All minerals fall into one of six categories: Cubic (Pyrite, Garnet), Tetragonal (Rutile, Chalcopyrite), Hexagonal (Beryl/Emerald, Hematite), Orthorhombic (Sulfur, Olivine), Monoclinic (Mica, Gypsum), or Triclinic (Amazonite, Turquoise). Some also include Trigonal/Rhombohedral (Calcite, Quartz) which is very similar to the Hexagonal system thus included with it. This is really only useful for perfect specimens that may indicate their crystal sytem.

And that's it! Next weekend will continue with the regular stone of the week series!

First Bead Show!

Sunday, January 6, 2008

So here's a picture of my loot from my first bead show. It's an Intergalactic Bead Show, and being held in Nashville, TN this weekend. The drive wasn't all too bad and it wasn't hard to find the fairgrounds where this was. Of course I loved the dichotomy of having a bead show in one building, and a gun show in another!

As you can see I ended up with mostly stone beads, some crystals, findings, and one lonely strand of pearls (a rariety for me). Frankly it seemed like I had bought a lot more than this while at the show - at least judging by how much I spent and how heavy my bag felt after 4 hours, lol.

It wasn't all that big, which in reality is a good thing I think cause I'd hate to imagine trying to get thru even more booths! All in all I figure there were around 20-25 booths, most of which were selling stone beads, a couple had metal beads and findings, and while there were a lot of little *cheap* pearls (like $4 or $6) there were few higher quality, more costly pearls.

The prices weren't all that bad either. A number of people felt that most beadshows would price things higher, and while I did find this at some booths, for the most part this wasn't the case. Of course the prices really varied from either pretty much what I'd pay for it online to great savings. What was great, was that many went ahead and charged whole sale prices because they didn't want to fool with the change in pricing. How do I know this? I overheard more than one seller tell a wholesaler that they couldn't really mark their stuff down more cause it was already marked down - some offered to take off a % if you bought in large quantities or $$, but many offered that deal to everyone not just wholesalers. So I benefitted from that. And a number of sellers were wanting to get rid of stock, so they had a lot of good stuff marked down.

The only disappointments were the lack of good white coin pearls (that were a fair price), and bulk earwires - most everyone sold no more than packs of 5 pair which surprised me. Biggest regret is not getting that strand of choclate brown and green stick pearls - they were fab!

My top 5 tips for going to bead shows after my little experience here, and drawing on my loooonnnggg experience going to rock shows:

1. Peruse all the booths first before buying anything (unless there's like only 1 of that item left in which case if you really want it, buy it). That way you don't spend all your money on the first few booths, when there may be something you'd rather had at another booth (or at a cheaper price!) Having a plan/list of things you want/need to look for helps with this too.

2. Bring cash - its quicker and easier to deal with, and sometimes sellers are more inclined to give discounts or round down prices if you do!

3. Bring a backpack, large purse, some kind of bag to put all your goodies in one place - better than holding onto a buch of bags while trying to look!

4. Check out the bead show's website for info about the show before going, and check for coupons either for admission, or from vendors.

5. Don't be shy. Don't let others force their way in line, or keep you from looking - if you try to be extremly polite and hang back for people to clear, it'll never happen. If you have questions, ask the seller, whether its about the quality, price, or material - you have the right to know before purchasing. Don't let sellers push you into buying something you don't want. I'm not saying be agressive or rude, but being assertive at a show (whether rocks or beads) is really the only way to do it - otherwise you'll likely end up miserable and not want to go again. (I know this makes it sound like people are rude/mean/inpolite, and most are actually not like this, but you will encounter it to some extent regardless, so its better to expect it).

Well that's it for now - its been a long day and I'm exhausted! Tomorrow (or should I say later today), I will finally get the Mineral ID post up!

Mineral ID update and Treasury

Thursday, January 3, 2008

Well I'm still working on that blog about Mineral ID - I aplogize for the delay, but I wanted to get some extra pics, plus it'll be a super-sized post so I hope its worth the wait! It will be up no later than this weekend though I'm shooting for tomorrow!

So in the meantime, here's a peek at my current tresury - inspired by last weeks Stone of the Week article on Malachite, seeing as it oxidizes from copper. Some really pretty stuff! It expires soon, so if you get the chance, check it out!