Author Gemology, Minerology, and Lapidary  (Read 2389 times)

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Re: Gemology, Minerology, and Lapidary
« Reply #30 on: March 31, 2016, 09:42:27 PM »
opals are fairly inexpensive if I remember correctly
That depends. Are you buying doublets or triplets ? They can be had for reasonable prices. Expect to pay $10.00 - $30.00 p/gram for good flash Mintabie black rough though.

The following are 'special' tones from a reputable dealer I've done business w/ before. Check out the pics. They carry some truly one of a kind gems if you jump back to their home page and search around. The catalog also showcases some of their unique gems.

http://www.pioneergem.com/SPECIAL%20STONES%20O%20to%20R.htm

Re: Gemology, Minerology, and Lapidary
« Reply #31 on: March 31, 2016, 10:09:25 PM »
These though are my favorites:

 ALEXANDRITE, CuA, 1.68 cts, 7.2x5.0 mm - One of the biggest of this RARE variety we have in stock now - An 85% change from pinkish beige to bright green - This one has a small feather in it so it is NOT clean - Hence the CHEAP price    $2,500/Stone


 ALEXANDRITE, CATSEYE, OV, 1.36 cts, 6.7x6.0 mm - The biggest Oval Cut we have at this time - RARE over one carat    $1,360/Stone


http://www.pioneergem.com/Special%20Stones%20A%20to%20F.htm


Did you guys also know that there are color change Garnets too ? Very rare.

 GARNET, COLOR CHANGE KENYAN, RD, 1.30 cts, 6.5 mm - The ONLY large 'Round' we have    $1,950/Stone


 GARNET, COLOR CHANGE MADAGASCAR, RD, 3.58 cts, 9.7 mm - A truly beautiful color change Gem - Changes from Pinkish/Red/Orange in incandescent light to Lavender/Pink in sunlight - Full 'open color' and CLEAN - You will like this GEM    $3,580/Stone


 GARNET, COLOR CHANGE STAR, RD, 0.86 cts, 5.6 mm - These are nice    $860/Stone

Re: Gemology, Minerology, and Lapidary
« Reply #32 on: March 31, 2016, 10:15:58 PM »
For natural crystals, it's hard to beat tourmaline:





Re: Gemology, Minerology, and Lapidary
« Reply #33 on: March 31, 2016, 10:17:50 PM »
I love fire Opal, but Labradorite is very cool as well.

Thanks for the links. I need to get some more grit for my tumbler. Have a bunch of Moss agate that needs polishing.
I've got some Labradorite, very interesting mineral, pretty too.
I also picked up some Tsavorite garnets before the price shot through the roof on them. :)

Re: Gemology, Minerology, and Lapidary
« Reply #34 on: March 31, 2016, 10:18:22 PM »
Did you guys also know that there are color change Garnets too ? Very rare.

No!  Those are cool.  I like garnets because the color reminds me of my favorite Negronis.

Re: Gemology, Minerology, and Lapidary
« Reply #35 on: March 31, 2016, 10:18:53 PM »
For natural crystals, it's hard to beat tourmaline:




Sweet - watermelon specimens. :)

Re: Gemology, Minerology, and Lapidary
« Reply #36 on: March 31, 2016, 10:24:24 PM »
I've always been partial to the now-almost-common moonstone.  There was a brief fashion for setting it in horn or tortoiseshell about a hundred years ago, which worked really well:




Moonstones also have mystical qualities. Bottom of the page gives geologic properties -->  http://www.healingcrystals.com/Rainbow_Moonstone_Articles_1191.html


Re: Gemology, Minerology, and Lapidary
« Reply #38 on: March 31, 2016, 10:33:42 PM »
Great thread. I collect rocks too, but especially meteorites. This is what iron and nickel looks like when it crystalizes in space in the core of an asteroid.


That's cool. I wonder how many diamond blades they went through to cut that. ;)

Re: Gemology, Minerology, and Lapidary
« Reply #39 on: March 31, 2016, 10:42:25 PM »
I totally do not believe humans & dinosaurs walked the earth together. Don't ask me why got decided to throw a rock at them.
LOL

This place would be pretty damn boring if we all agreed on everything. ;)

Both sides of the debate:

http://paleo.cc/ce/dino-art.htm

http://www.apologeticspress.org/apcontent.aspx?category=9&article=446

Re: Gemology, Minerology, and Lapidary
« Reply #40 on: April 05, 2016, 02:18:14 AM »
this is...fantastic


Re: Gemology, Minerology, and Lapidary
« Reply #41 on: April 05, 2016, 02:38:03 AM »
this is...fantastic



Wow.  I had no idea.

Re: Gemology, Minerology, and Lapidary
« Reply #42 on: April 06, 2016, 02:35:27 PM »
this is...fantastic




Saw a documentary on these giant crystals.  Notice the guy's full body suit?  I think the heat in there would kill after a couple minutes without protection.  Totally airless too, if I remember right.  And humid too...even the crystals are sweating.  I think that the explorers were limited to like twenty minutes or so before having to get back to a safer spot.     

Re: Gemology, Minerology, and Lapidary
« Reply #43 on: April 06, 2016, 08:10:57 PM »

Saw a documentary on these giant crystals.  Notice the guy's full body suit?  I think the heat in there would kill after a couple minutes without protection.  Totally airless too, if I remember right.  And humid too...even the crystals are sweating.  I think that the explorers were limited to like twenty minutes or so before having to get back to a safer spot.   

interesting...

Re: Gemology, Minerology, and Lapidary
« Reply #44 on: April 06, 2016, 08:20:30 PM »

Saw a documentary on these giant crystals.  Notice the guy's full body suit?  I think the heat in there would kill after a couple minutes without protection.  Totally airless too, if I remember right.  And humid too...even the crystals are sweating.  I think that the explorers were limited to like twenty minutes or so before having to get back to a safer spot.   
upwards of 136F and 90-99% humidity. Sounds very pleasant.  ;)
https://en.wikipedia.org/wiki/Cave_of_the_Crystals
http://www.discovery.com/tv-shows/other-shows/videos/discovery-atlas-mexico-mine-of-naica/

Re: Gemology, Minerology, and Lapidary
« Reply #45 on: April 06, 2016, 09:23:10 PM »
this is...fantastic


You guys beat me to it. :)

Yes, 15 minutes maximum with the suits on.

Re: Gemology, Minerology, and Lapidary
« Reply #46 on: April 06, 2016, 09:24:52 PM »
Top Spots For Gem Hunting In The US

https://www.gemsociety.org/article/mined-in-america/

Re: Gemology, Minerology, and Lapidary
« Reply #47 on: April 06, 2016, 09:55:32 PM »
The worlds most rare gemstones.There's some beauties in here. :)

https://www.truefacet.com/guide/top-10-rarest-gemstones/


Re: Gemology, Minerology, and Lapidary
« Reply #48 on: April 06, 2016, 10:24:44 PM »
So where do you start if you want to try your hand at faceting ?

http://www.bwsmigel.info/geol.115.essays/considering.faceting.html

Ultra-Tec Review  https://www.gemsociety.org/article/just-ask-jeff-review-ultra-tec-faceting-machine/

Faceting machines are not cheap by any means. Local geology clubs will sometimes also have used machines up for sale though at reasonable prices.

Re: Gemology, Minerology, and Lapidary
« Reply #49 on: April 07, 2016, 05:33:05 AM »
A small geode might look interesting unless it was cleaved, gee beav?  Think it might be worth sumthin?

I keep hold of small hunks of limestone that have even the most basic fossils embedded, as far as gems?

hah, I say.

Chances of wandering around and finding any kind of gem-stone quality rock in the wild are astronomical unless you live in the geographic area where they are plentiful, and even then good luck if humanity has been around for awhile.

Not saying you won't find something by blind luck, but getting rich?  Anymore, if it has an interesting weather pattern I might stoop to pick it up, locally I am seeing gravel chunks from WAY far afield from my locale.

Still fun to look.

Heck, I have a couple of unpolished stones I picked up from underfoot in the 'stan that are green, red and black.  Indigenous gravel?  I couldn't say, but probably, hope is to polish them into some sort of souvenir, probably not the gold filigree thingamabob but whatever. 

I doubt the three colors of raw stone gravel were native to the particular spot I happened to spend a year.  Call me a smuggler...

Re: Gemology, Minerology, and Lapidary
« Reply #50 on: May 20, 2016, 07:07:57 PM »
opals are fairly inexpensive if I remember correctly
It totally depends on the type of opal and if they are doublets or triplets. Black opal (mainly from Lightening Ridge & Mintabie) with good fire can range upwards of thousands to hundreds-of-thousands of dollars an ounce. Luckily, opals are very light-weight.

1 Ounce = 141.747616 Carats
1 Troy Ounce = 155.517384 Carats

Here's a nice specimen: https://www.opalauctions.com/auctions/black-opal/black-opal-stones/item-591926

from this site: https://www.opalauctions.com/auctions/black-opal/

Re: Gemology, Minerology, and Lapidary
« Reply #51 on: May 20, 2016, 07:21:34 PM »
A small geode might look interesting unless it was cleaved, gee beav?  Think it might be worth sumthin?

I keep hold of small hunks of limestone that have even the most basic fossils embedded, as far as gems?

hah, I say.

Chances of wandering around and finding any kind of gem-stone quality rock in the wild are astronomical unless you live in the geographic area where they are plentiful, and even then good luck if humanity has been around for awhile.

Not saying you won't find something by blind luck, but getting rich?  Anymore, if it has an interesting weather pattern I might stoop to pick it up, locally I am seeing gravel chunks from WAY far afield from my locale.

Still fun to look.

Heck, I have a couple of unpolished stones I picked up from underfoot in the 'stan that are green, red and black.  Indigenous gravel?  I couldn't say, but probably, hope is to polish them into some sort of souvenir, probably not the gold filigree thingamabob but whatever. 

I doubt the three colors of raw stone gravel were native to the particular spot I happened to spend a year.  Call me a smuggler...
Love your posts pate, but I've got to disagree with you on this one. Always check streambeds no matter where you are. Lots-O-Goodies. ;)    Do'em sum scopen hereaboutseses  http://gemhunter.webs.com/ und http://diamond1872.blogspot.com/


Whaaa ?
http://geo.msu.edu/extra/geogmich/kimberlites.html

http://www.mindat.org/loc-28944.html

http://articles.chicagotribune.com/1985-06-30/news/8502120059_1_diamonds-geologists-iron-ore

Ediotski: You're right though, don't expect to get rich from it unless you are trained in geology and know what to look for. Most peeps will mistake rough diamonds for quartz. The best tool to have with you in the field is a set of hardness picks. ;)

Re: Gemology, Minerology, and Lapidary
« Reply #52 on: June 01, 2016, 05:47:13 PM »
I collect rocks. I don't go out as often as I used to, but I still hit up a couple of the fire agate sites we've got out here from time to time.

Re: Gemology, Minerology, and Lapidary
« Reply #53 on: September 16, 2016, 03:46:50 PM »
...
 Btw, in response to another thread, have you heard the Solutrean hypothesis Hypothesis that links Clovis Culture to the Solutreans in Europe? Very controversial. But there have been odd "finds" that often disappear due to the new laws on "Indians" but the Clovis points etc can still be seen in museums or found.
Yup, heard of it. I've never believed in the theory isolationism, yet it's still promoted as a fact when in reality, the supposed experts don't have a stinking clue - but it fits their agenda, and keeps the grant money coming.

Re: Gemology, Minerology, and Lapidary
« Reply #54 on: September 16, 2016, 04:13:48 PM »
Excellent mineralogy database HERE



90's style website, but excellent information.

Here's a copy paste of part of their page on Corundum, of which this months' birthstone (Sapphire) is a species of.

Corundum Crystallography
Axial Ratios:    a:c = 1:2.72995
Cell Dimensions:    a = 4.751, c = 12.97, Z = 6; V = 253.54 Den(Calc)= 4.01
Crystal System:    Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: R 3c
 X Ray Diffraction:    By Intensity(I/Io): 2.085(1), 2.552(0.9), 1.601(0.8),




Lewis J , Schwarzenbach D , Flack H D , Acta Crystallographica, Section A , 38 (1982) p.733-739, Electric field gradients and charge density in corundum alpha-Al2O3

 
Physical Properties of Corundum Cleavage: Cleavage:    None
 Color:    Blue, Red, Yellow, Brown, Gray.
 Density:    4 - 4.1, Average = 4.05
 Diaphaneity:    Transparent to translucent
 Fracture:    Tough - Difficult to break apart as shown by fibrous minerals and most metals.
Habit:    Euhedral Crystals - Occurs as well-formed crystals showing good external form.
Habit:    Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Habit:    Tabular - Form dimensions are thin in one direction.
Hardness:    9 - Corundum
Luminescence:    Sometimes Fluorescent, Long UV=red.
Luster:    Vitreous (Glassy)
Magnetism:    Nonmagnetic
Streak:    none
 
Optical Properties of Corundum
 Gladstone-Dale:    CI meas= 0.089 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.08 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1905,KPDmeas= 0.1886,KC= 0.207
Ncalc = 1.83 - 1.85
Optical Data:    Uniaxial (-), e=1.76, w=1.768, bire=0.0080.
 
Calculated Properties of Corundum
 Electron Density:    Bulk Density (Electron Density)=3.93 gm/cc
note: Specific Gravity of Corundum =4.01 gm/cc.
Fermion Index:    Fermion Index = 0.0002259597
Boson Index = 0.9997740403
Photoelectric:    PECorundum = 1.54 barns/electron
U=PECorundum x rElectron Density= 6.08 barns/cc.
Radioactivity:    GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Corundum is Not Radioactive
 
Corundum Classification
Dana Class:    04.03.01.01 (04)Simple Oxides
     (04.03)with a cation charge of 3+ (A+++2 O3)
     (04.03.01)Corundum-Hematite group (Rhombohedral: R-3c)
     
    04.03.01.01 Corundum Al2O3 R 3c 3 2/m
     
    04.03.01.02 Hematite Fe2O3 R 3c 3 2/m
     
    04.03.01.03 Eskolaite Cr2O3 R 3c 3 2/m
     
    04.03.01.04 Karelianite V2O3 R 3c 3 2/m
     
    04.03.01.05 Tistarite! Ti2O3 R 3c 3 2/m
 Strunz Class:    04.CB.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
     04.C - Metal:Oxygen = 2:3, 3:5, and Similar
     04.CB -With medium-sized cations
     
    04.CB.05 Auroantimonate* AuSbO3 Ortho ? Ortho
     
    04.CB.05 Geikielite MgTiO3 R 3 3
     
    04.CB.05 Brizziite-III NaSbO3 R 3 3
     
    04.CB.05 Brizziite-VII NaSbO3 R 3 3
     
    04.CB.05 Ecandrewsite (Zn,Fe,Mn)TiO3 R 3 3
     
    04.CB.05 Corundum Al2O3 R 3c 3 2/m
     
    04.CB.05 Eskolaite Cr2O3 R 3c 3 2/m
     
    04.CB.05 Hematite Fe2O3 R 3c 3 2/m
     
    04.CB.05 Karelianite V2O3 R 3c 3 2/m
     
    04.CB.05 Ilmenite FeTiO3 R 3 3
     
    04.CB.05 Melanostibite Mn(Sb,Fe)O3 R 3 3
     
    04.CB.05 Pyrophanite MnTiO3 R 3 3
     
http://webmineral.com/data/Corundum.shtml


Re: Gemology, Minerology, and Lapidary
« Reply #55 on: September 16, 2016, 04:14:24 PM »
Here is a slab of rock that I use as a paperweight while at the computer.  It's four inches wide and 3/4 inch thick.  I don't know what kind of rock it is, though it appears to be agatized.  It is polished clear on one side and the other is not clear at all but if you hold it up to the sun you can see the rock's interior quite nicely. 

My computer desk has an elevated shelf to the right where a lamp sits.  Unfortunately, I have moved the lamp closer on occasion and the darn thing falls over onto the rock.  You can see some chips where the edge of the lamp's metal hood has hit the poor paperweight.   

Re: Gemology, Minerology, and Lapidary
« Reply #56 on: September 16, 2016, 04:23:25 PM »
Cool. Translucent, and it looks like it was a double formation geode. The inner formed, then there must have been a temperature drop, then the outer, larger section formed. That's a unique specimen.
Thank you for posting it.
Do you have a set of hardness picks ? My guess would be somewhere in the neighborhood of 5-7 mohs.

Re: Gemology, Minerology, and Lapidary
« Reply #57 on: September 16, 2016, 04:38:38 PM »
Sapphire rough gallery. This is what they look like in the wild. Good page load times.

http://www.mindat.org/gm/3529

         

Re: Gemology, Minerology, and Lapidary
« Reply #58 on: September 16, 2016, 04:51:45 PM »

Re: Gemology, Minerology, and Lapidary
« Reply #59 on: September 16, 2016, 05:05:31 PM »
Rix, here's a quick, down & dirty way to test hardness. http://www.oakton.edu/user/4/billtong/eas100lab/hardness.htm

More detail: http://geology.com/minerals/mohs-hardness-scale.shtml

Wow, thanks Logan I will work on it.  Also, thanks for the info on the paperweight.  I bought it at an antique mall, haha.  I don't do it very often but once in awhile I peruse ebay for rocks and fossils.  Here is one I bought a couple years back.  If the seller knows what he's talking about, this seven inch wide rock shows a specimen of a Pecopteris Fossil Fern.  The fern formed when the world was united into one large land mass called Pangea, centered around the equator making for lush, moist forests of tree ferns and the like.  This fossil was taken from the Carboniferous Period of Pennsylvania.  300 million years old and counting.  lol  It's fun to hold something like this in your hands and ponder those long ago days.