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Yttrium Fluorite

Posted by Kristi Hugs  
Kristi Hugs January 13, 2012 05:42PM
Good Morning,
I have just purchased some Yttrium Fluorite but cannot find a lot about it at all! I know that Yttrium is a rare earth inclusion and is found in just a few mineral specimens. I know that this type of Fluorite does not cleave like other Fluorites. I am pretty sure that it only comes from Mexico. So my assumption is that Yttrium Fluorite is a Var. Fluorite with Yttrium inclusions. Would that be correct? I cannot find anything on about Yttrium Fluorite specifically, so am really not sure if I am going in the right direction or not. I did look in my Peterson Field Guide of Rocks and Minerals as well as my Audubon Field Guide (North America) but did not find yttrium in either.

Any assistance you could give would be most appreciated!!

thank you,
Reiner Mielke January 13, 2012 06:05PM
Looks more like agate to me, how hard is it? Also see this:

Edited 1 time(s). Last edit at 01/13/2012 06:06PM by Reiner Mielke.
Kristi Hugs January 13, 2012 06:11PM
No, it is not an agate. I am 100% sure it is Yttrium FLuorite :) it is very soft, easily scratched.
Thank you for the link, however, I am not sure they are the same. This particular lavender is found in Mexico. I did not see that in the information shared. Thanks for the help though! Every bit helps!! :)

Edited 1 time(s). Last edit at 01/13/2012 06:14PM by Mira Bai.
Stephanie Martin January 13, 2012 06:29PM
Since this is a sliced slab difficult to determine from a picture. Hardness test would not be conclusive. I would try testing for carbonates to rule them out.

The green fluorite from the William Wise Mine is reported to have Yttrium causing the fluorescence (and perhaps other REEs).

Good luck with your search.

stephanie :-)
Kristi Hugs January 13, 2012 06:45PM
Thank you !! I know the ID of the piece. I am 100% sure of that. What I am looking for is information on Yttrium Fluorite. Is it Fluorite with Yttrium inclusions? Is that what makes it the pale lavender color? Since it has no cleavage, is it the fluorite that is the purple color and the yttrium that is included that makes it pale? Is mexico the only source? if so, why? is there something there that there is not anywhere else in the world?

these are the kind of things I am looking for :) The ID of the piece is not in question, so I have removed it since the ID is not what I am asking for help on :) it is the content I am needing the help with :) Thanks for your input! all is helpful!!

Edited 2 time(s). Last edit at 01/13/2012 06:47PM by Mira Bai.
Dan Fountain January 13, 2012 06:57PM
Perhaps yttrofluorite?
Kristi Hugs January 13, 2012 07:03PM
Reiner was kind enough to post that info earlier. I am not sure they are the same due to the fact that mexico is not even listed in the locations? I will add that to my research just in case :) thanks so much!
Stephanie Martin January 13, 2012 07:36PM
In a google search I found a metaphysical site that is selling this material.

I am providing the link as the site has pictures of the botyoidal rough material which is better for reference.

The listing indicates that 20% of the calcium has been replaced by Yttrium. Someone has tested this somewhere?

Perhaps some of the Mexican fluorite experts can shed a light on a more precise locality which may lead to published information on the fluorite analysis from there.

hope this helps
stephanie :-)
Stephanie Martin January 13, 2012 08:16PM
This ebay seller claims it comes from a cave formation. Are we getting closer?
Peter Andresen January 13, 2012 09:22PM
an other healy-fealy-fake!?
Kristi Hugs January 13, 2012 09:32PM
No, it is not fake, Peter :) It is real. I know well respected, reputable dealers that have sold it. I am currently doing some research on old scientific papers (thanks Rock Currier!) about Yttrium. I believe I read on Google where this was only found in Mexico, however, upon further study, these particular pieces were cut from Brown's Canyon District, Colorado. I also found out that Yttrium is not an inclusion. It is, in its own right, what is called a "rare earth". There are tests on this rare earth (scientific papers) that mention Yttrium back as far as the late 1800's. As far as how and when Yttrium Fluorite was first found or if there is another more accurate name, I am still researching. Thanks for all the suggestions and help!

Peter Andresen January 13, 2012 09:41PM
Well, since the element Yttrium haven't been found as a native form in nature, what you have is yttrian-fluorite (and if you look at it chemicaly, you would probably never have the possibility of natural yttrium in a fluorite). But if you want to be sure, why not get it analysed?
Stephanie Martin January 13, 2012 09:41PM
You may already have this one, but here is another paper on Colorado material.
Kristi Hugs January 13, 2012 09:49PM
Thank you Stephenie, that was very helpful!
D Mike Reinke January 13, 2012 10:24PM

I have Dana's New Mineralogy, and it mentions pale violet Fluorite from Naica Mexico, but doesn't elaborate on it. Mentions the SG of "yttrian or cerian fluorite". Can i ask what your confidence is in it's identity? i just ask because chemistry is complicated stuff. Lots of things observed aren't totally understood, so answers to good questions can be lacking, -sigh-
Take care,

W Laird Fowler January 13, 2012 10:36PM
There's a rock shop in Llano, Texas that has some experience with fluorite and rare-earth minerals. You can contact him at:

Enchanted Rocks & Jewelry
805 Berry St.
Llano, Texas 78643

The Central Mineral Region of Texas has numerous rare-earth localities including Yttrian & fluorites; unfortunately they are on private ranches and/or under flood control lakes. He might be able to give you some identification tests you can try.

Dean Allum January 13, 2012 11:02PM
You have silicified fluorite, a mixture of silica and fluorite. Here is a picture of where it comes from in Browns Canyon near the Arkansas river.
Browns Canyon

It is more of a sedimentary fluorite in this area. It used to be mined by the ton and used as flux for the steel mill in Pueblo, Colorado. It should contain traces of yttrium only because of the nearby granite. That is, it probably fluoresces in ultraviolet light.

True yttrofluorite or "Yttrium Fluorite" will be radioactive due to trace thorium content. It is found in several of the Colorado pegmatites.

Another easy verification check for yttrofluorite is a specific gravity greater than 3.2 g/cm^3. You will find that your stuff has a S..G. less than 3.0.

This silicified fluorite is attractive. I have a couple of boulders of it in my rock garden.

-Dean Allum
Keith Compton January 13, 2012 11:23PM

I can't see your pic of the specimen and I know nothing about Mexican Fluorite but if I recall correctly Colorado was part of Spanish Mexico so if you are researching old papers they may refer to the locality as being in Mexico.

Kristi Hugs January 13, 2012 11:25PM
I am following up with the vendor on the location since I am the one that appears to be confused on that one. The vendor I purchased this from is well respected, very knowledgeable, has been in the business for over 25 years and knows her stuff. I do not question that at all. I am 100% sure of what I have. So please, trust me when I say testing is not necessary.

My original question was, could someone tell me more about it.? I know it does not have the cleavage Fluorite is known for, in fact, I read that it has no cleavage. Whether that is true or not, I have not followed up on just yet. It is my understanding that Yttrium has replaced some of the calcium. I have been reading various scientific papers on the subject, one of which, if you are interested, you can look at. Stephanie shares the link in a previous post. I took down the original picture because people were trying to identify it. I know what it is, I do, I really do.......i just wanted to know more about it...that's all :)
open | download - Yttrium 7.jpg (315.4 KB)
Doug Daniels January 14, 2012 06:47AM
I would hazard a guess that what is being sold as "yttrium fluorite" is what Dana's System of Mineralogy calls "yttrian fluorite". Merely a variety of fluorite with some calcium being replaced by yttrium (one reported analysis has the ratio Y:Ca as 1:6), with the touchy-feelies not knowing how to change the reference to the element. This old (1951) reference suggests the variety tends to be massive or granular, and colorwise is yellow, brown, violet, or blue (aren't these colors rare in fluorite????). No specific locations are cited. So, to verify that you actually have "yttrian fluorite", you would need a chemical analysis of your specimen - there is no simple test, visual or otherwise, that will tell you that a fluorite specimen contains yttrium.
Kristi Hugs January 14, 2012 03:51PM
Thank you for your information Doug. I must tell you, as a "touchy feelie" I am dedicated to sharing both geological and "touchy feelie" information, which is why I am here, to get the facts. It is interesting to me that the fluorite with yttrium in it is called Yttrian. Why not just call it what it is? Here in lies my confusion I suppose. I have attached a picture in the post previous to yours so that you can see what this fluorite looks like.
Dan Fountain January 14, 2012 04:03PM
Mira Bai Wrote:
> It is interesting to me that the fluorite
> with yttrium in it is called Yttrian. Why not just
> call it what it is?

Yttrian is an adjective meaning "containing yttrium". Calling it "yttrian fluorite" IS calling what it is. Calling it "yttrium fluorite" is not.
Kristi Hugs January 14, 2012 04:35PM
Awesome! thank you!
Dean Allum January 14, 2012 05:48PM

Mindat and most geologists use mineral names approved by the International Mineralogical Association. You will notice the date on the above reference paper is 1958. Most copies of Dana's System of Mineralogy are also dated prior to 1960. The name "yttrian fluorite" was discredited during the 1960s and replaced with "yttrofluorite".

I have 2 references to the Browns Canyon district, and pictures of similar material I have collected there, but am hesitant to post them. You may be happier not knowing the whole story.

-Dean Allum
Kristi Hugs January 14, 2012 06:01PM
Hey Dean,

Thank you for the info. I am in contact with the vendor to see if they were just cut/sliced by someone in Colorado and are from some other place or if they were cut, as in mined, in Colorado. I am not clear on that just yet :)

I guess I am different from your average touchy feelie......I want to know the truth, the whole truth and nothing but the truth when it comes to geological info, so give it to me :) I can handle it :) I am far more concerned about having integrity that I am giving half of the truth :)

thanks for your post. It is very helpful!

Dean Allum January 14, 2012 11:24PM
Below is the relevant text from two books.

'Colorado Rockhounding' by Stephan Voynick 1994

page 65: "The Browns Canyon fluorspar-mining district, eight miles northwest of Salida, covers six square miles between the Arkansas River and U.S. Highway 285. Between 1929 and 1950, Browns Canyon ranked among the top U.S. fluorspar districts, with twenty mines producing over $5 million in fluorspar. Fluorite mineralization occurs along a four-mile-long fault section as veins of fluorite associated with chalcedony; accessory minerals are barite, calcite, pyrite, iron and manganese oxides, and small amounts of opal. Browns Canyon fluospar ores are white or gray, with light shades of red, brown, and green. The fluorite, mostly botroidal and nonfluorescent, ranges in color from pink and yellow to green, purple, and white. Nodular growths, with fluorite forming concentric bands around breccia fragments, also occur. In the 1950s, lapidaries cut and polished nodular specimens into attractive display pieces"

'Minerals of Colorado' by Edwin Eckel 1997

Page 210: "Browns Canyon District. This district, which has produced large quantities of fluorspar, is 8 miles northwest of Salida and lies between the Arkansas RIver and U.S. Highway 285. The fluorite occurs as veins in granitic and volcanic rocks. Most is white and fine-grained. It occurs as bands along faults and as large irregular masses that are botroidal, mammillary, or even stalactitic. At the Morgan Ranch deposit, veins of fluorite, ranging from a few inches to 4 feetin width, cut granite and the overlying lava flows. The fluorite is fine-grained and porcelanic to sucrosic textured and is beautifully banded in shades of green, pink, purple, red, brown, or white. The fluorite deposits now incorporated in the Browns Canyon Wilderness Area were reviewed by Leibold and others (1986)."

Page 215: "Yttrian Fluorite from the White Cloud pegmatite occurs in large anhedral cleavage masses up to several feet across. The yttrian fluorite is present between the intermediate zone and the core of the pegmatite with synchysite-(Y) and other REE minerals. ... Simmons and Heinrich and Wayne discussed the occurrence of yttrofluorite and the REE mineralogy of the White Cloud pegmatite. The fluorite is typically opaque, pale tan in color and has a distinctive pinkish white fluorescence under SW UV."

On the left are two purple banded silicified fluorite slices from the Browns Canyon district. They have a specific gravity of 2.97 My lighter material is covered with snow right now.
On the right are two brittle, ugly euhedral yttrofluorite crystals from the White Cloud pegmatite. They have a specific gravity of 3.24, are radioactive and contain synchisite or bastnasite inclusions. They would not make nice jewelry.

-Dean Allum
open | download - Fluorite_yttrofluorite.JPG (415.2 KB)
Kristi Hugs January 14, 2012 11:37PM
Thank you Dean!!

This information is good to know!! I have seen the silicified Fluorite before. It was sold to me as "Tiffany Stone". Nice to know what it really is! Very good to know about the radioactive stuff too! LOL I am waiting to hear from my vendor to see if this stuff came from Colorado and if it has been tested.

So here is a question for you. Is light able to be seen through the silicified Fluorite? Would light be able to be seen through Yttrian Fluorite? Is there a difference in hardness? (I am thinking silicified would be harder than the soft Yttrian? Sorry if my terminology sucks......I am learning slowly :)

thank you so much for taking the time to post this for me. I am truly appreciative!!!

D Mike Reinke January 15, 2012 12:09AM

If you've been posting for 5 years apparently you can take it. I like dependable dealers too, but you can understand the skepticism you were hit with, can't you, when your trusted authority is in the business end of this field, not academic, and also hasn't put you wise to the correct name of what you bought?
If you can get a good approximation of the minerals' SG, you can really be satisfied. The SG of agate is what, 2.6? Fluorite3.2, and yttrofluorite, "up to 3.6" (Dana's) With a digital scale and some kitchen equipment you can at least come close, unless there is matrix...
I thought Dan and Stephanie were most helpful, too. Put me wise, so thanks for bringing this subject up.

Kristi Hugs January 15, 2012 12:14AM
Hey Mike,

Yes, I can take it and yes, you are correct, I do understand the skepticism. I know if I mentioned the names, they would probably understand why I am so sure that this stuff is legit, but don't want to bring up names, ya know? Then again, if I am wrong and I bring up the name, then that would not look good either :) Not sure that makes sense, but anyway.....

I have a digital scale and a kitchen full of equipment. How do I get a relatively close SG?

Dan and Stephanie were most helpful. Dean too :)
D Mike Reinke January 15, 2012 06:28AM
Yes, makes great sense.
If I understand it right, weigh the piece grams or ounces, lets say ounces, on a scale, then submerge it in water in some clear, calibrated measuring cup, and find how much volume it displaced. if you put that piece in 8 ounces of water, and then the water went up to 10 ounces, that piece's volume is two ounces. if your scale read a weight of 7 ounces, let's say, then your SG is 3and1/2, about what y-f would be. If the scale weight was, say, 5. 4 ounces, your SG is closer to 2.7, like quartz. The problem is getting the volume accurately enough, because fractions of an ounce you could be only estimating. A jolly balance is a more accurate scale for SG, if you have the use for it.
So it is a ballpark figure, not exactly high-tech.
If anyone else has a better idea or procedure on SG, I'm all ears.
So does THIS make sense?!

Kristi Hugs January 15, 2012 05:24PM
I weighed the piece. It is 5.03 ounces.
I placed this piece in 10 oz of water. It went up one hash mark. Maybe just a tick above.




- <----- once the piece was placed into the water, the water went up to here. So that would be 11.25 ounces


So 1.25 is the volume. correct? (11.25 - 10 =1.25)
and 4.02 would be the SG? (5.03 divided by 1.25 = 4.02)

Sorry, I am bad at math :) is that close?


Edited 5 time(s). Last edit at 01/15/2012 05:58PM by Mira Bai.
Stephanie Martin January 15, 2012 06:23PM
Hi Mira,

In order to get an accurate reading, the specimen must not touch the sides or bottom of the vessel, it must be suspended in the water, usually using a thread or string or such.

stephanie :-)
Kristi Hugs January 15, 2012 06:35PM
OK! good to know :) I will try it again :)
D Mike Reinke January 15, 2012 07:20PM
For a guesstimate, that looks pretty good. You can skip the '.02' because this is only a ballpark figure. but that is heavier than I expected, so I'm at a loss to explain it. Maybe try it w/ something you know the SG of that is pure, one minerl, and see if you come close the established SG. Either way, have fun sleuthing.

Kristi Hugs January 15, 2012 07:34PM
Hey Mike,
Stephanie suggested that I tie a piece of string and suspend the piece, instead of just letting it drop to the bottom. I am going to try again using that technique and see if it will improve (give more accurate) the numbers. Stay tuned!

Kristi Hugs January 15, 2012 07:47PM
Ok, well the string tieing experiment came up like this:

I used a slab that weighed 2.5 oz
The slab itself measures 2 1/4" x 1 3/4" x 1/2"
I used 20 oz of water as I wanted to make sure the piece was submerged in the middle by the string and not touching the bottom or the sides.
The water only moved up 1/2 of a hash mark (each hash mark = 1.25 oz, 1/2 of a hash mark would be 0.63) which would make the 20.63

So, using these new figures,
the volume is 0.63 (20.63 - 20= 0.63)
and 3.97 would be the SG (2.5 divided by 0.63 = 3.97)

I must be doing something could the SG be more than the weight of the specimen? Maybe I need a cup with more accurate markings. Hmm, maybe I should find one of those jolly things........LOL
Noah Horwitz January 15, 2012 08:30PM
Fluorite sold as "yttrium fluorite" that looks sort of similar to your material has been analyzed by X-ray Fluorescence Spectroscopy (XRF) and no yttrium was detected. See I don't know the detection limit of this measurement, but it's certainly lower than 20%. That's not to say that your sample contains no yttrium for sure, but I would suspect it doesn't.

Purple color in fluorite is commonly attributed to "color centers" - defects in the crystal structure consisting of (in this case) a free electron sitting where a fluoride ion should be in the lattice. See for more info. This is probably the cause of color whether your fluorite contains yttrium or not.

As for specific gravity, it's definitely OK for it to be larger than the weight of the specimen, since it's measuring something different than weight. Specific gravity is a measure of density, how much a given volume of a substance weighs. Density is specific to a material; for example, a 1 cm cube of gold would weigh 19.3 g, and a 10 cm cube of gold would weigh 19.3 kg, but both would have the same density, because both are made of gold. Even a small flake of gold weighing only a few mg would still have this same density.

Therefore, Mike's suggestion to use some standards makes a lot of sense. Any sample of quartz, or iron, or copper, or aluminum, etc. should have the same density and your measurement can be compared to the known density of these materials. Good luck with the measurements!

(As an aside, density depends on the units you use for weight and volume. In this case, you used ounces and fluid ounces, so your density is in units of oz./fl. oz. Specific gravity is density relative to the density of water, which is 1 g/mL or about 1 oz./fl. oz., so the units you used do give a measure of SG)
Dean Allum January 15, 2012 09:47PM
While I am calling the rock from Browns Canyon "silicified fluorite" it is actually a sedimentary mixture of fluorite and chalcedony. It has a specific gravity between the two. It is only translucent when it gets as thin as ~2mm. While it is hard enough to act as jewelry, it is soft enough to smooth and polish with wet sandpaper.

My yttrofluorites have had their crystalline structure destroyed by their radioactivity and are not transparent at all.

You should be commended for attempting to make specific gravity measurements. This is a relatively easy way to help identify specimens. I don't think you have been given enough info here to make an accurate calculation. Please refer to this earlier thread about it. Most S.G. methods are based on the fact the water has a density of 1.0 gram per cubic centimeter.
Specific Gravity Thread

Good Luck,
-Dean Allum
Kristi Hugs January 15, 2012 09:50PM
Thanks everyone!! This has certainly been educational! I don't know how or where to get a piece tested, or even how much something like that would cost, but I am relatively sure I have enough information to somewhat accurately describe the specimens to my customers. You all have been very very helpful! Thank you!

D Mike Reinke January 15, 2012 10:50PM
You are still more or less at SG of 4, so I'd go w/ that. But if quartz materials are @ 2.6, and ytt-fluorite is 'up to 3.6 SG', you have something else in the mix, it would seem to me.
1 oz. volume of water is, well, one ounce weight! (Wow, there is a revelation!) So w/ quartz, 1 oz. volume of quartz. is 2.6 ounces, wt. A cup (the usual 8 oz. glass of water) is half a pound, right? so a cup of quartz would be 20.8 ounces in weight. Get my drift? (Gold, at SG 19, one ounce wieghs 19 ounces, etc....
I found a blocky hunk of chert in a stream bed that weights in near 21 pounds. a gallon of water is 8lbs.,(2.6X}= 20.8lbs, so i call the piece my "gallon" of chert.
So your piece is heavier than your average stone of that size. It should feel 'heftier' in your hand
I appreciate Noah's explanation of the free electron in the fluoride spot in the lattice. That helps.

hope this helps,

Kristi Hugs January 15, 2012 11:03PM
I am learning so much! wow! Yes, it does feel heftier in my hand. I don't know if it helps in the process if I share that I can shine a light through it, even though it is 1/2" thick or not? Does that help in the info for a determination or is that just, I can shine a light through it? :) I have attached the piece I used for the SG test and the same piece with light behind it.


PS, I am honestly so thankful that you scientific folks are being so patient with a non scientific folk like myself :)
open | download - yttrianunderlight.jpg (338.7 KB)
open | download - yttrianpossibly.jpg (440 KB)
Doug Daniels January 16, 2012 03:54AM
As far as the SG calculations go, there is a slight error. In your examples, you were calculating the density of the sample using weight ounces and fluid ounces. This can give some erroneous results; converting weight (actually, mass) to grams and volume to cubic centimeters (cc) gives better results. In your first run, you measured the weight as 5.03 oz; this converts to 142.6 g (28.35 g/oz). The volume was estimated at 1.25 fl. oz., which converts to 36.96 cc (29.57 cc/fl oz). Thus the density of the sample is 142.6 g/36.96 cc, or 3.86 g/cc; dividing by water's density of 1 g/cc gives an SG of 3.86, which is *^^$ close to any value for fluorite, yttrian or vanilla. Not to shabby. Thing to remember with the kitchen measurements is that small errors in volume measurement can give large errors in calculated density, and thus the SG.

And this just for the heck of it. Seems that yttrian fluorite may be a "new find" for the crystal movement folk. Maybe because of all the recent interest in the rare earth elements and their seemingly magical properties; yttrium is considered to be on of them. Possibly someone in sales "discovered" this variety of fluorite in the literature, and decided it would help sales of otherwise boring fluorite. Of course, how to know that a given specimen is yttrian or not is beyond me. Also, it seems that the purported properties of yttrian fluroite may be different than reguler fluorite (otherwise, why distinguish them?). If so, if you buy a specimen hoping for the properties of the one, but actually have a specimen of the other, seems you would be subject to at least bad karma, or at worst like taking the wrong medication for some affliction. Just sayin'.
Kristi Hugs January 16, 2012 05:39AM
Thank you Doug.

Although I think you blew my brain up on the first paragraph, i think I followed :)

As for the second paragraph, as I giggle, I will say, point taken :)
Bill Baker Barr January 16, 2012 06:21AM
Mira and all,

A few notes from a fluorite fanatic:

I bought some lapidary material called yttrian fluorite (rounded chunks, not slabbed) from a respected dealer in New Mexico; reportedly it's from Mexico. It's banded in light purple shades. I was hoping it would be fluorescent - other yttrofluorites in my collection fluoresce yellow under shortwave UV - but it doesn't glow. I'm assuming it's actually fluorite but haven't tested it, losing interest because of the lack of fluorescence.

A simple hardness test: if it isn't scratched by a copper penny (pre-1982) or a piece of calcite, but is scratched by a piece of apatite or a knife blade, the hardness is around 4 on the Mohs scale, so it could be fluorite.

A great reference book, Mineralogy for Amateurs by John Sinkankas, has instructions for building a simple but very accurate specific gravity scale out of a piece of balsa wood, some scrap lumber, a paper or cloth sewing measuring tape (metric), a single edge razor blade, a beaker, some thread and a paper clip - total cost maybe 5 bucks. The one I built is accurate to about 1%, using fairly small pieces of the mineral being tested. You might be able to find the book in a library, borrow it from a dedicated mineral collector, or buy it online at or It's well worth having, with tons of useful information including field collecting tips, mineral data, and lots more identification test equipment and procedures. Using its instructions, I also made a working calcite dichroscope (shows dichroic and pleochroic colors) and a polarizer (differentiates amorphous and cubic system samples from those that crystallize in other systems).

And now some philosophical content: In my deeply-considered opinion, there's no bad reason to love a rock...

Kristi Hugs January 17, 2012 03:16AM
Bill, I so totally agree with your philosophical statement :) and the rest too! thanks, it is really great info!!

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