Monday, June 30, 2008
PrettyRock.com: Specific Gravity Precision Checker
How accurate is specific gravity? Dev put together a quick reference chart and an SG Scale Precision Checker that allows you to see how accurate (and inaccurate!) the measurement of SG can be depending on the precision of your scale. The precision of the scale and the weight of the stone being weighed are critical to getting an accurate measurement of specific gravity.
Sunday, June 22, 2008
Monday, June 16, 2008
PrettyRock.com: International Schools of Gemology Comparison Chart
When I started researching where I wanted to take gemology classes, I had a hard time comparing all the different choices. So, I have put together this chart to help compare schools. Trying to find all the information on each school can require some digging, so this is a work in progress. If you can help fill in any of the blanks, please let me know.
http://www.prettyrock.com/international_schools_of_gemology.htm
I've finally decided on the distance classes at GIA (Gem-A was a close second!) I like that I can take the program one class at a time, and have been very happy with the class materials. I've finished the diamonds class and am in the middle of the colored stones class. I'll be taking the lab classes in August and can't wait!
If you are looking for great information with a much smaller price tag (as in free or close to it) try the International Gem Society or Dr Barbara Smigel's Online Class. Both are fantasitic resources for rockhounds!
Thursday, June 12, 2008
PrettyRock.com : How to use Refractometer
We have updated our refractometer instruction / tutorial page.
http://www.prettyrock.com/refractometer-instructions.htm
Please let us know if anything is unclear, or if you still have questions.
http://www.prettyrock.com/refractometer-instructions.htm
Please let us know if anything is unclear, or if you still have questions.
Monday, June 09, 2008
Gemology Myths
1
All spectroscopes have wavelength scales.
Most gemological spectroscopes do not; the wavelength scale requires a 2nd tube.
2
You only have to do one test to identify a gemstone.
Most gemologists conduct at least 3 tests if not more.
3
All gemstones have an absorption spectra.
Most clear stones tend not to have an absorption spectra, or it is so fine as to be unreadable with handheld tools.
4
All you need is a refractometer to identify gemstones.
A refractometer is very helpful, since the refractive index (RI) is very unique for gemstones. But the caveats include:
Some stones are very close to each other by RI.
Some stones can range broadly as the impurities are different from locality to locality.
Some stones are off the scale, over RI 1.80 for most refractometers.
The refractometer cannot detect synthetics or treatment which you need to know.
5
Gemologists only use brand name gemological tools.
Some gemologist insist this is the only way to go. If your customers are image conscious, then it might be worth the extra thousand dollars. But if your customers appreciate value, then you can use tools that are just as accurate and save you money which is why PrettyRock.com is here!
6
All gemstones are natural.
While many gemstones are natural, synthetics have become more and more prevalent. Multiple tests have been devised to differentiate natural gemstones from synthetics.
7
Only natural gemstones are valuable.
Some synthetic gems are more valuable than natural gemstones! For example, a synthetic hydrothermal emerald gemstone is worth more than a clear quartz gemstone of the same size and quality.
8
Only untreated, natural gemstones are valuable.
Many treated natural gems are very valuable, and some synthetics are not cheap. Take Paraiba tourmaline for example, which can be heat treated and still worth $1000's per carat.
9
Bought it as [[pick a gem]]. It has to be [[pick a gem]]. Variations include:
My jeweler can't miss.
Has to be true, saw it on TV!
From my grandmother, so it must be alexandrite.
Family heirloom, must be ruby.
Look how old it is, doesn't age count for amethyst?
Unfortunately, we all make honest mistakes. And there are some who make a living at it. Most jewelers are honest so don't feel like you have to be paranoid. At the same time, always learn for yourself or get more than one opinion from people you can trust or who don't have a vested interest. The best example is to never, ever sell your gemstone or family heirloom to an appraiser who just told you what it was worth and then offered to buy it! Along the same lines, if you are a year or two into gemology, admit that you still have alot to learn! This will help you save face when you want to dig your heels in during a debate. Back away slowly, do your research, and come back for more when you know more.
10
All gems are suitable for jewelry
Many gems are much too soft for jewelry. Others are too soft for rings but should be safe enough for earrings unless you plan on banging your head against the wall!
11
Sapphire is only blue.
Sapphire comes in many colors from pink to purple, to clear, to yellow or padparadscha!
12
Diamonds are rare.
The truth is that cheap diamonds are rare. Geologically speaking, diamonds are as plentiful as tourmalines which puts them on the fairly common side of gemstones. For investments, choose natural untreated rubies or high quality emeralds.
13
Generic gemological equipment can not compare to brand name equipment.
PrettyRock.com has used most gemological equipment available in the market. We are very pleased to see that our value-focused high quality instruments are very accurate and offer an excellent alternative to high priced brand-focused products that can cost thousands more to purchase.
14
All rubies are valuable.
Some rubies look like gravel and that is true for any gem material. But there are some natural rubies that have been extensively treated to fill in cracks and cover inclusions that make them far less valuable than merely heated treated rubies or the much more esteemed all natural rubies. Even all natural rubies must be over one carat then have very good clarity and color to be valuable.
15
I found it gem digging; I'm rich!
There is no measuring sentimental value. I still have my biggest and ugliest garnet found while gemdigging sitting like a precious trophy in my collection. Most gemdigging finds are worth more as the memories they bring back to us.
16
Gemological tools come with instructions.
Gemological tools have not normally come with instructions because they were sold to professionals , but they do now! PrettyRock.com has listened to our customers, and recognizing the strong interest from the public in this fascinating field, we are including brief and concise instructions with our gemological instruments.
17
Gemological tools are easy to use.
Just like riding a bike (for the very first time.) Most tools take some diligent reading and some generous patience. Refractometers are easiest, then dichroscope, polariscope and much farther down the line is the spectroscope.
18
Only diamond can scratch glass.
Any gem material harder than glass at Mohs 5.5, can scratch it, quartz, tourmaline, topaz, garnet, sapphire, etc.
19
Diamonds are unbreakable.
Diamonds are very breakable, due to their cleavage plane. If struck along the cleavage plane and diamond can easily shear off along the plane and leave you with two diamonds!
20
Opals and pearls make great rings.
Opals and pearls are soft and will abrade over time in a ring which takes heavy wear.
21
Diamonds are always worth more than other gemstones.
The value of diamonds is currently maintained by a cartel that restricts supply. Because diamonds are as common as tourmalines, they would be worth as much as tourmalines if supply were unrestricted.
22
WANTED: One gemological tool to identify them all.
I want one too! An appropriate identification requires multiple tests and even more tests are required to distinguish natural gems from synthetics.
23
Gemstones can be identify from a photograph.
This has been attempted and requested many times! It is woefully inaccurate and lots of fun.
24
Must use GIA tools to get Graduate Gemology degree from GIA.
No, you can use any gemological tools available to get your degree. We offer a value-focused, high quality alternative to the brand-focused high priced products from GIA.
From http://www.prettyrock.com/gemology-myths.htm
All spectroscopes have wavelength scales.
Most gemological spectroscopes do not; the wavelength scale requires a 2nd tube.
2
You only have to do one test to identify a gemstone.
Most gemologists conduct at least 3 tests if not more.
3
All gemstones have an absorption spectra.
Most clear stones tend not to have an absorption spectra, or it is so fine as to be unreadable with handheld tools.
4
All you need is a refractometer to identify gemstones.
A refractometer is very helpful, since the refractive index (RI) is very unique for gemstones. But the caveats include:
Some stones are very close to each other by RI.
Some stones can range broadly as the impurities are different from locality to locality.
Some stones are off the scale, over RI 1.80 for most refractometers.
The refractometer cannot detect synthetics or treatment which you need to know.
5
Gemologists only use brand name gemological tools.
Some gemologist insist this is the only way to go. If your customers are image conscious, then it might be worth the extra thousand dollars. But if your customers appreciate value, then you can use tools that are just as accurate and save you money which is why PrettyRock.com is here!
6
All gemstones are natural.
While many gemstones are natural, synthetics have become more and more prevalent. Multiple tests have been devised to differentiate natural gemstones from synthetics.
7
Only natural gemstones are valuable.
Some synthetic gems are more valuable than natural gemstones! For example, a synthetic hydrothermal emerald gemstone is worth more than a clear quartz gemstone of the same size and quality.
8
Only untreated, natural gemstones are valuable.
Many treated natural gems are very valuable, and some synthetics are not cheap. Take Paraiba tourmaline for example, which can be heat treated and still worth $1000's per carat.
9
Bought it as [[pick a gem]]. It has to be [[pick a gem]]. Variations include:
My jeweler can't miss.
Has to be true, saw it on TV!
From my grandmother, so it must be alexandrite.
Family heirloom, must be ruby.
Look how old it is, doesn't age count for amethyst?
Unfortunately, we all make honest mistakes. And there are some who make a living at it. Most jewelers are honest so don't feel like you have to be paranoid. At the same time, always learn for yourself or get more than one opinion from people you can trust or who don't have a vested interest. The best example is to never, ever sell your gemstone or family heirloom to an appraiser who just told you what it was worth and then offered to buy it! Along the same lines, if you are a year or two into gemology, admit that you still have alot to learn! This will help you save face when you want to dig your heels in during a debate. Back away slowly, do your research, and come back for more when you know more.
10
All gems are suitable for jewelry
Many gems are much too soft for jewelry. Others are too soft for rings but should be safe enough for earrings unless you plan on banging your head against the wall!
11
Sapphire is only blue.
Sapphire comes in many colors from pink to purple, to clear, to yellow or padparadscha!
12
Diamonds are rare.
The truth is that cheap diamonds are rare. Geologically speaking, diamonds are as plentiful as tourmalines which puts them on the fairly common side of gemstones. For investments, choose natural untreated rubies or high quality emeralds.
13
Generic gemological equipment can not compare to brand name equipment.
PrettyRock.com has used most gemological equipment available in the market. We are very pleased to see that our value-focused high quality instruments are very accurate and offer an excellent alternative to high priced brand-focused products that can cost thousands more to purchase.
14
All rubies are valuable.
Some rubies look like gravel and that is true for any gem material. But there are some natural rubies that have been extensively treated to fill in cracks and cover inclusions that make them far less valuable than merely heated treated rubies or the much more esteemed all natural rubies. Even all natural rubies must be over one carat then have very good clarity and color to be valuable.
15
I found it gem digging; I'm rich!
There is no measuring sentimental value. I still have my biggest and ugliest garnet found while gemdigging sitting like a precious trophy in my collection. Most gemdigging finds are worth more as the memories they bring back to us.
16
Gemological tools come with instructions.
Gemological tools have not normally come with instructions because they were sold to professionals , but they do now! PrettyRock.com has listened to our customers, and recognizing the strong interest from the public in this fascinating field, we are including brief and concise instructions with our gemological instruments.
17
Gemological tools are easy to use.
Just like riding a bike (for the very first time.) Most tools take some diligent reading and some generous patience. Refractometers are easiest, then dichroscope, polariscope and much farther down the line is the spectroscope.
18
Only diamond can scratch glass.
Any gem material harder than glass at Mohs 5.5, can scratch it, quartz, tourmaline, topaz, garnet, sapphire, etc.
19
Diamonds are unbreakable.
Diamonds are very breakable, due to their cleavage plane. If struck along the cleavage plane and diamond can easily shear off along the plane and leave you with two diamonds!
20
Opals and pearls make great rings.
Opals and pearls are soft and will abrade over time in a ring which takes heavy wear.
21
Diamonds are always worth more than other gemstones.
The value of diamonds is currently maintained by a cartel that restricts supply. Because diamonds are as common as tourmalines, they would be worth as much as tourmalines if supply were unrestricted.
22
WANTED: One gemological tool to identify them all.
I want one too! An appropriate identification requires multiple tests and even more tests are required to distinguish natural gems from synthetics.
23
Gemstones can be identify from a photograph.
This has been attempted and requested many times! It is woefully inaccurate and lots of fun.
24
Must use GIA tools to get Graduate Gemology degree from GIA.
No, you can use any gemological tools available to get your degree. We offer a value-focused, high quality alternative to the brand-focused high priced products from GIA.
From http://www.prettyrock.com/gemology-myths.htm
Wednesday, May 28, 2008
Polishing your refractometer's hemicylinder
Check out this blog post at tiptopgem for information on polishing your refractometer's hemicylinder.
Wednesday, May 21, 2008
William Holland Trip May 2008
Dev and I went to William Holland Lapidary School aka Rock Camp in Georgia last week. We had a blast! It has to be the best deal in a vacation around. They are a nonprofit organization that offers classes in faceting, cabbing, beading, metal work of all kinds, just about anything to do with rocks. We took the opal class and are now addicts. I think we are going to need his and hers Pixies now. We have already signed up to go again this summer to take Silver I. Any other Hollandites here?
(A little plug. Check them out here: http://www.lapidaryschool.org/ $310 for the week includes your room, meals, and the class. There is usually a nominal lab fee depending on the class taken. Opals supply fee was $20, but I imagine something like gold work would be quite a bit higher. )
Friday, October 05, 2007
Friday, May 04, 2007
Tuesday, May 01, 2007
Wednesday, April 25, 2007
Quartz with Petroleum and Bituminous Inclusions
Very cool rock! Dev and I were offered a parcel this by a rough dealer who knows my love of inclusions. It is herkimer like quartz with petroleum (the yellow liquid) and bituminous solid inclusions. This particular piece also has a three phase inclusion of an air bubble that moves with the solid in the petroleum! I think it is my favorite rock of all time. I started a thread on the Mindat.org message boards: http://www.mindat.org/mesg-11-61219.html They are such a wonderful, knowledgeable group. Some of the best mineralogists in the world hang out there!
Friday, April 13, 2007
National Geo. Article: Giant Crystals
http://news.nationalgeographic.com/news/2007/04/photogalleries/giant-crystals-cave/index.html
Very cool.. huge crystals found in Mexico!
Very cool.. huge crystals found in Mexico!
Tuesday, April 10, 2007
More from Tucson : Amazing Opal Eggs!
We saw the most amazing opal eggs at the InnSuites show! I collect eggs, so I was drooling on the cases.
It is really hard to capture the beauty of opal in a photograph. This show a little of the wonderful play of color in this egg. (If you have to ask how much....)
Tuesday, March 20, 2007
Inside a Sunstone
One of our customers sent me these sunstones as a surprise! Thank you Jim! I wanted to get a closer look at what caused the shimmer inside the stone. These are taken with a camera mounted on a microscope:
Information on sunstone:
Purple Rock mystery solved
It's lab-grown, chromium-bearing alum K(Al,Cr)(SO4)2 . 12H2O . The very nice people on the mindat message boards helped me out.
Sunday, March 18, 2007
Big Purple Rock
This is the big purple rock I got in Tucson. It was sold as Halite, but after some research I think it might be sylvite? It does dissolve in water, and it tastes salty/bitter (don't try this at home kids!) BUT I can find no images like this on the web any where. Both halite and sylvite usually have cubic crystal formations. It is about 14" x 6 " x 4" Very brittle, streaks white, Any ideas out there?
Friday, March 02, 2007
AKS Gem Shows - LaQuinta and Howard Johnson
These two shows have merged in my brain, and I am not sure which photos are from where! They are right next two each other, and no real clear definition between them...at least not to my rock tired mind. They are both run by AKS.
Outside at La Quinta. I got interesting rock here. It was labeled as halite, but it isn't. I think it is a Russian synthetic amethyst. We saw little piece of it at another show, a little piece of it for $35. I'll try to get a photo of it up here. Whatever it turns out to be..it was a bargain! 
Display of rough...please don't drool on the glass.
Giant geode with calcite crystal. The box is about the size of a pizza box and says DO NOT TOUCH...so of course we had to. Boy did we get a dirty look!
A gorgeous stone carving...I love the way the light comes through the wings.
Giant fossils (I think they are ammonites?)
Fire opal dealers at the Howard Johnson.
Everyone is required to have the picture taken with a giant rock at least once!
Pueblo Gem and Mineral Show (River Park)
The next show we went to was the Pueblo Gem and Mineral show (to add to the confusion, it is also called River Park ) We had lunch at the Bennigans there. We were early and got served very quickly. Maybe a little too quickly, Dev's burger was still mooing. Being the in intrepid rockhound that is he, he ate it anyway. After all.. there were rocks to see!
There is so much to see. It's hard to know which direction to look first.
Pink Kunzite and aqua...I think!
The gentlemen from Poor Boys Opals out of Australia were very gracious in sharing their knowledge about opals from Lightening Ridge.
This dealer had some wonderful mineral specimens!
Two boys show us what the Tucson show is all about! Amazing rocks and enthusiasm!
There were several vendors working in their booth. This one is working on a cabbing machine. A cab is a gem or stone that has a smooth domed surface.
There is so much to see. It's hard to know which direction to look first.
Pink Kunzite and aqua...I think!
The gentlemen from Poor Boys Opals out of Australia were very gracious in sharing their knowledge about opals from Lightening Ridge.
This dealer had some wonderful mineral specimens!Thursday, March 01, 2007
Days Inn, Rapa River, River Park
On Day 2 in Tucson, we went to the Days Inn, Rapa River, RiverPark (formerly Pueblo Inn in the morning. Amazing shows and hard to see everything! We actually got there a little early (still on east coast time) and many of the vendors were just starting to open. One funny thing that happened was going to a pearl dealer there. I picked out a few pearls including one neat one that showed the growth patterns. I asked what the total there and of the 4 people standing there, none of them could help me. Turned out the one lady who knew how to price the pearls was still at breakfast. I am not sure of the point of the other "helpers"... oh well, never did get back there for my pearls.
One of the great things about gem and mineral shows is the opportunity to meet people from all over the world. Just at this one show we met people from Nigeria, Russia, Thailand, China, Brazil, Afghanistan and more.
Here are some photos from Days Inn:
One of the great things about gem and mineral shows is the opportunity to meet people from all over the world. Just at this one show we met people from Nigeria, Russia, Thailand, China, Brazil, Afghanistan and more.
Here are some photos from Days Inn:
As with most of the shows in Tucson, this show was both in the rooms, out in tents, and in the "ballroom."
Some gorgeous rock sculptures. I love the way they are inspired by the natural shape and colors of the stone to create these landscapes.
Dev checking out some rough.
An amber dealer's booth.. it was just stunning when the light hit it.
Big ol' hunks of malachite.
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