Introduction and Help with Refractometer

[ValerieV22113]

Hello. I live in the lower half of Louisiana’s boot, about 60 miles north of New Orleans, which is where I am from. As a young girl, I formed a labeled collection of shells and rocks collected on trips across the country on some shelves in the hall closet.

About twenty years ago, I collected and studied dzi beads and carved and decorated carnelians and agates from ancient cultures in the east. I had to sell that collection and still could kick myself for selling my favorite bead; a pinkish orange etched with cuniform in black carnelian. I would pay a fair price to have that back, but alas it is gone.

About four years ago, we got some loads of big rock and I noticed anomalies in color, size and shape from what I was use to seeing, mostly on gravel roads her in Louisiana, and away I went.

Since then I have read, read some more, handled, had polished, tested and learned over and over and over. One piece of equipment led to the next, to the next and so on.

When I first began picking up these stones and handling them, I was very sure they are ancient (I understand that all stones are ancient) in the sense they had been specifically chosen and shaped by ancient indigenous cultures. I guess I knew this because I had handled so many ancient stones from the east. I have come to learn in order to know stones, you must handle them.

There are many ancient native tribes known to this area, but part of me feels these are much older. The variation on color, size, type and shape is astonishing to have found, in my mind, here in Louisiana, where we don’t have massive rock.

What we do have is rivers and plenty of them, some of them appearing to be offshoots of the proposed Paleo Bell River. And of course, we have the mighty Mississippi.

In this area we have had the massive asteroid impact in the Gulf of Mexico, theorized to have extincted the dinosaur and in that same area, an extinct volcano 8,000 feet below the Gulf.

What Happened the Day a Giant, Dinosaur-Killing Asteroid Hit the Earth

There is also some very good evidence there was a similar strike, on a smaller scale, in the next parish over, not far from where I live.

At any rate it has been my insatiable curiousity about how these stones came to be here which has culminated in “The Refractometer” which I have been trying to use correctly for the last month. Here are my main issues and I hope someone can either help or lead in the right direction. I have read and looked at every article and video on the internet and it’s not helping appreciably.

1. This is a GIA Duplex II, gray in pretty good condition. I polished the hemicylinder and can see a distinct turquoise green line. However, it moved from the bottom up, distinct from the dark area of 1.81 and NOT from the top as most tutorials indicate it should. This is WITHOUT the magnifying lens, which is the only lens which came with it. With the lens, the very faint line, not always greenish, moves from the top down and without, the very distinct green line moves from the bottom up.

2. Spot reading cabochons has not worked. The RI liquid is fine and I can see the shape of the stone contact but when moving my head, the shadow of the stone blinks from dark to light with no discernible half light half dark I can see.

That’s for starters! I have been really reticent to come forward before now, because after four years of study, I know more than I did, but not enough! It’s a very complex subject. I do have other interests but I love my rocks!

Here’s some photos.

Thanks in advance for any help.

[ValerieV22113]

Am still hoping someone can help with the refractometer questions. I have worked really hard to try and identify these stones.

I feel if I can get a handle on this piece of equipment, I can get some answers as to what these stones are. If I know what they are, then maybe I can find out, eventually, where they came from. I simply can’t afford to send every stone off for identification.

I sent one off and it cost $165.00 and for that money, all I got was a refractive index. Then I knew it was citrine. So, I figured it would be much cheaper to buy my own refractometer and try and find the answers myself.

I started with written research and photos, then progressed to a Presidium Gem Tester II. Then I added in specific gravity (which I seem incapable of performing), mohs hardness sticks (very good tool) uv lights, both long and short wave, immersion of a sort with benzyl benzoate and just feeling the heft of a stone.

I’ve studied particular stone’s habits and crystal shapes. I even tried to facet with a diamond disc on a turntable because I can’t afford a faceting machine.

My refractometer has a removable lens in a silver color and not the black color I see on brand new models.

I’ve talked to jewelers, hobbyists, club participants, a university, etc. I can’t impose my time on every single rock when every one else is busy too.

So, thanks again and I hope to hear from someone.

[ValerieV22113]

I forgot to add I’ve been through six dremels and oodles of sanding discs and polishing pads.

[PaulB36648]

Hi and welcome to the forum. I have a very low end refractometer and I too struggled to get the hang of it. IMHO, it requires time to get a feel for how it works, but when it clicks, it becomes quite routine. If you’d like, please PM me and we can jump on a call and I can try and walk you through it, but here are a few suggestions that helped me. These may not be helpful, and others may have better suggestions, but these helped it “click”.

Note: I am a total armature, so I apologize in advance if I state the obvious, or state things not very well; I’m just sharing what helped for me.

First, ignore the make/model and the polarizing lens for now, I think the basic device is the same at that price point, no matter the make/model, and it was important for me to look at a simple picture of the device and grok the basic concept: a light source goes in one end, bounces off at least one mirror, and is directed at a refractive liquid underneath the stone. That liquid has known, fixed refractive properties against which the scale where the refraction can be measured in the viewfinder. So you need the right fluid, or the refraction of said light may not be calibrated to your device/scale. I assume the device came with fluid. It is theoretically possible the fluid you have is not right for your device, I thought so did, but it turned out I just didn’t have the hang of it, the fluid was/is fine.

Someone pointed out to me on this forum that you cannot get any reading on some stones, so keep that in mind. I can doe most, but that was super helpful to know, I wasted a lot of time on trying to measure unmeasurable stones. The other thing to note is that at the extreme end of the range of the scale (for my device, lower than roughly 1.35 or higher than 1.8, I can’t really measure accurately (if at all). So if you are trying to measure diamonds or even zircons (for me), don’t bother. The point is (again for me), if it’s measurable, the line should be pretty clear. If it is not clear, I find that changing the light source can make a huge difference. Mine came with a yellow LED light, which usually works pretty well, but sometimes not at all; and if i remove it and stick a white light flashlight in front, or hold it up to bright natural light, the line is clear. Additionally, if the surface of the stone is not flat and essentially flush against the fluid/lens surface, you won’t get a reading (so forget about most cabochons). Finally, you don’t need much fluid at all, a very tiny drop will do, about a millimeter, or even less. Try putting a dry stone on the lens and see what you see, and then add the fluid and take another look. It’s the latter look and feel you want, or don’t bother trying to see a line.

To summarize, first try and get a line, any line, and maybe use a stone that isn’t finicky, like a tourmaline or an amethyst. Those are usually easiest for me to see.

Don’t worry about turning the stone or using the polarizing filter until you get to this point. Job one is to see a clear line, I humbly posit.

At the risk of making your challenge worse through bad or unclear suggestions, I’ll stop there. I think I covers the main things that got me started (the amt/type of fluid, the light source, the flatness of the stone surface, and the measurability of the stone itself. I don’t know why the light source makes a huge difference for me, but at times it’s night and day; I see a line with one source, and nothing with another.

Regarding SG, that should be pretty straight forward but here’s a few things I had to learn to take decent measurements:

Th smaller the stone versus the volume or water, the harder (and likely less accurate) the reading. It was hard for me to find a way to tie small stones in a cradle to dip in the water until I stumbled upon using very thin gauge copper wire (like 22 guard or less; you don’t want to wire/string to effect the measurement. I think two decimal places on the scale are essential, and I’d invest more in a good quality scale than reflectometer; a flukey scale is a real pain. I use very thin walled, light weight plastic container in a few sizes, and i cut away any plastic on the rim above the min depth I need to submerge the stone. Again, the less the volume of water relative to the size of the stone, the easier it is. I can get decent readings about about 1.15-1.25 carats in a thimble size plastic container, but below that, I don’t bother.

I hope this helps. Again, amateur advice but thats what I needed, so I hope it works for you.

.

[mdsandifer]

These are common stones.

[DanielB66512]

Here is the thing…

To use a refractometer the stone must have a flat surface. It also needs to allow light to pass through it. From the looks of the pictures of stones you send, the refractometer isn’t going to help you. It really is designed for faceted gemstones. Hope this helps!

[ValerieV22113]

Thank you, but they are not common to here where they come from.

Some of them are common in general and some of them are not.

As always, it is difficult to tell anything from photos but what I was simply trying to show was
the diversity of color from one area.

I’m sorry if I did not explain myself clearly. I only wanted to know if an older GIA Duplex reads the RI from the bottom if you don’t have the magnifier on it.

[ValerieV22113]

Thank you Daniel. I know there has to be a flat surface, unless you are reading a cabachon.

Most, not all, of these stones are transparent and transluscent. You just can’t tell from the photos.

I’ll just keep working with it. Thanks anyway and appreciate the replies.

[ValerieV22113]

Paul, thank you! I did discover a yellow flashlight I bought seperately does not work as well as a small, white light flashlight. That was a recent discovery.

Where I get confused is everything I’ve seen, except for one article, states and shows the green line coming from the top down. However, that is with the magnifying lens.

One article said while getting an RI on a cab, you take the reading from the bottom of the reflected shadow of the stone in the viewer.

It’s a very good refractometer, though used. Of course I had to buy the RI seperately and it is 1.81.

You’re very sweet to have explained the SG. I guess I really so have to master that.

Many of the stones have an internal core different from the exterior, but some do not.

Have a wonderful day.

[MichaelC47202]

@ValerieV22113

cuniform in black carnelian

I recently acquired red onyx necklace of beads which is incredibly heavy and would be a very difficult item to wear. Bought for less than cost of a lunch. If wanting a certain type of bead buy the type then break item apart and use into your designs. I do not need the 1,000 carats of red stone which came with necklace but was a good buy. Red of all colors. Onyx generally is black and very heavy in large beads.
I bought a really heavy necklace so I could get the beads. Clasps are silver and for entire necklace under $20 was good buy.
Shop. Only but if you see potential or can create from what you buy.
I bought around 60 pounds of loose beads which amount to several thousand beads.
I also acquired loose rubies which I will drill holes into for creating necklaces, bracelets, earrings, rings if I find extra silver. Overall be creative.

[ValerieV22113]

Thank you Michael! I will consider your advice.

[StevenH26783]

not common where you are located for sure… residual pebbles from upstream across the whole mississippi river drainage… expect that they are collection of everything. however common river rocks from an uncommon location doesn’t part intrinsic value as gems. Still pretty though so enjoy them.
so far as refractometer use, if you have the model number and make, should be able to look up the user’s manual online… practice on something that is known and easy to work with, like glass and clear quartz…for higher refractive indices, try it on a diamond in jewelry if you have one…cabochons are harder due to curved surfaces…darker ones could be rocks, like lapis which are nont single mineral… just one confounding factor…
just keep on trying and you will get the hang of it… best of luck… you do have pretty stones, looks like mostly agates.

[ValerieV22113]

Thank you Steven.

Yes. It just fascinates me so many different types ended up in one spot. Mostly chalcedony. Agates, quartz, Jasper, moonstone, garnets, citrine, etc.

However, many have different cores from the outside. They were all found as is, except I polished them with a dremel. Many of them appear to have been shaped and/or worked in some way. We had many, many native american peoples here over what I believe to be many, many thousands of years and if we are fascinated with stones, then surely they were too and must have seen or understood the intrinsic value of their uniqueness, which is how I see them.

Some of them would make unique and beautiful gemstones, albeit not expensive. What I posted is only some; I have a Husky full of stones of all sorts of patterns, shapes and types. In fact, I have way too many stones and some could view it as a bit of an obsession.

I got the user manual and really think it is poorly written and explained. But, I guess it’s like learning to ride a bike. You don’t how until you do know how.

Have a wonderful day and thanks.

[StevenH26783]

User’s manuals are unfortunately poorly written. technical writing has been severely degraded over the last decade. Stuff made in China tends to be worse with the user’s manuals.

If some of the are ancient Native American artifacts you have a quandry on your hands. Ancient artifacts are illegal to trade in, if acquired on federal public lands. Not much public land in Lousiana but some… 1.3 million acres… Artifacts generally would be made out of hard rocks and knapped into tools. They would have sharp edges, ie., arrow heads, scrapers… if they were transported downstream by water, some of the edges would have smoothed, but the shape would be retained. I came across a Mogollon cuture (pre Anasazi) midden by the side of the road in far southwest New Mexico… tons of potsherds, agate chips, a scraper…it had been undiscovered by archeologists. Did not want to take artifacts as archeology depends on contextural evidence. The stone tools all would have had razor sharp edges, as the agate was flaked… the flakes were very sharp. You mentioned that the rock was trucked in by the tons. Were these transported from another area as road fill?..pebble deposits often are used as road fill in places where there is no hard rock nearby that is quarried and crushed to be suited for the purpose. If so, the rock was most likely a sedimentary unsolidated layer. Floods could have moved and later normal water flow concentrated them… it would help to know where they came from.

The Chicxulub asteroid stike occurred 66 million years ago… the continental US still had an inland waterway, the Atlantic was much smaller and the present day LA was underwater. The pebbles would not be related to the asteroid strike. Most of the rock in a high velocity collision is vaporized, thrown out as dust in small fragments or melted into glass (tektites)…basement rock is shattered and does get thrown far distance also. The Chicxulub strike is noticeable for a high sulfur content as it hit limestone…the iridium anomaly at the KT (also known as the KPg) boundary is world wide… the mass exinction that ended the dinsoaurs and closed out the mesozoic era is marked by the anomlous concentration of iridium …In Texas, geologists who were looking for another strike in the Brazos river area found debris from the Chicxulub strike… a gigantic tsunami washed up rocks. Shock quartz also found. Don’t think it was a separate strike…coesite and stisovite are high pressue/moderate temperature quartz phases… found in ecglotite facies metamorphism in deep crust other than shocked quartz. An alternate explanation, the eruption of the large igneous province, the Deccan traps, has also been proposed as the mechanism that killed off the dinosaurs along with an estimate 60-80% of all species. However, this theory is controversial. Despite a deep mantle plume origin (Renion hotspot), the iridum concentration is low…Iridium and other platinum group metals partion into earth’s iron core.

[ValerieV22113]

Hello Steven and thank you.

My husband has a small dump truck and in addition to getting rocks for our property, I am also allowed to collect from the gravel pit, as we are purchasing there.

I don’t believe my stones are tools. If they have anything to do with Native Americans it would be impossible to tell, really. It just seems odd to me that the chalcedony as I have found it, is already “tumbled” by nature with many of them just seeming to be too perfect or smooth.

All of my speculations are just that; speculations in an attempt to explain what I find to be an incredible amount of different colors, to have all ended up in a gravel pit in Louisiana. I’m sorry but I thought I was clear about what area of the world they came from and where they ended up.

Just one or two loads in a small dump truck of big rock can yield an awful lot of stones. My husband just sort of does it as favors for people we know. We purchase the stones.

However, I can concur with you on the roads. Some of the rocks of which our gravel roads around here are made, and those which are the base in most of our paved roads, would have rocks bought in on containers from other places via train and containers delivered to docks on the Mississippi River, where DOTD would purchase them.

But, around this part of Louisiana, the land becomes mostly clay based in the higher areas, and you can clearly see where road cut thrus and old creek cut throughs have layers of different materials with stones embedded in the layers. So, many of the stones used for the roads, came from local sources. I have picked up one or two specimens from roadways and ditches which turned out to be beautiful.

And too, we humans and science in particular, don’t know everything about earth’s history yet. All scientfically based things are possible.

I love information like you and others have given. Maybe I should have been a geologist.

[ValerieV22113]

I forgot to say that I read about the KT boundary about four years ago and had forgotten that incredibly interesting fact. Thanks for reminding me of it.

[ValerieV22113]

While we’re on the subject, one thing I’d really like to know is whether the shapes, as you can see them, are normal shapes these stones are commonly found in?

That question has been at the forefront of my curiousity since I first found them.

[StevenH26783]

gravel deposits happened in mud floor rivers… flooding washes down rocks from upstream… they collect in turns on a riverbed, build over centuries, until the river meanders elsewhere… at turns, the water moves faster and washes the gravels clean… the fact that they were almost tumble polished is characteristic of gravel beds in river… the rocks get naturally tumble polished by water full of grit and sand… muds can have small hard microscopic mineral grains in them also…the moving water cleans them and they accumulate in piles… sand bars are the same except the grains are much smaller… they can form in muddy water also… can’t tell what the conditions were in the remote past when the gravel beds were formed… the river that put them there has long changed course…

[ValerieV22113]

Thank you Steven.

My original hypothesis was they had come from Montana, from a bursting of a dam that had happened, or perhaps some had washed down from the mining flood next to the Missouri River in the early 1900’s, where all was lost.

Without getting too personal, I couldn’t walk for a while (all fine now) but during that period, I would sit in this enclosed rose garden where I had the stones put and just sift through them. I still do. There are also a lot of them as a bed in our barn. You couldn’t tell what any of them looked like but I knew something was different.

They were all so filthy grey and dusty, it took many soakings of water and Murphy’s Oil Soap before I could begin to see what they were.

Though I collected rocks and shells when I was little, I hadn’t really looked at them since then. I was born and half grew up in New Orleans. We moved to the Northshore of Lake Pontchatrain which is where I live now, but higher up. We didn’t have rocks in New Orleans. So, this is all new to me.

I’ve spent the past four years picking through rocks, cleaning them, polishing them, testing them, holding them, learning all about them.

I contacted the chief of a native tribe here in Louisiana, because I felt if they were native american then I didn’t have a right to them. He was very nice and even offerred to have someone he works with call me.

I contacted a University in Montana, hoping someone would be interested in chemically testing some of them, just so I could see where they came from.

I have not intention of becoming a professional gemologist. I was just at this point in my self education where I joined IGS, hoping to get even more info.

The stones fascinate me and kept me interested when I could do very little. Now I’m hooked. It’s the history of humanity. Minerals. How could you not be hooked?

[StevenH26783]

HIghly unlikely that heavy material would have washed all the way down the Missouri to New Orleans… possible but not likely.
If you like stones, read up on it… buy some basic books on minerals and rocks… the simon and schuster field guide to minerals and rocks and the same field guide series to gems has characteristic pictures and all of the chemical and physical properties of minerals and gems. Have to start with the basics… the revised Dana’s Mineralogy is also a classic… I am no longer collecting… finding them with friends and giving them away is as much as I want to collect anymore… went from rock hound as a kid to jewerly hobbyist. Now hobbyist in geology and geochemistry… not professional but purely an amateur and hobbyist in geochemistry, geophysics… still have learned enough and keep on learning new developements in trace element isotopic systematics. I am currently attending the annual Goldschmidt meeting of the international and european geochemistry societies… all of it is PhD research presentations… I can understand and follow geochemical models, having read textbooks on the subject at the 300 and 400 college geology level… absolutely need to have a strong background in chemistry, physics. My own profession was medical science… subspecializing in a field that uses computed fourrier analysis to obtain power/ frequency spectra in time, laplacian tranformation adds topography… as a medical scientist, I know chemistry and biochemistry… and also electrical circuitry in mathematical form… Now that I am retired, I can follow my own interests…
Would have never been able to understand trace element signatures and isotope systematics without being interested in rocks as a kid… I memorized the stoichometry formulae, crystal classes for common minerals as a kid…read mineralogy… had to approach it scientifically…’

I cannot over emphasize how important it is to start learning and make it a life long habit. Books are a start… ChatGPT can be a great help and become a personal tutor but you will get no where on line unless you know exactly what questions to ask of it… all of the world’s knowledge and disinformation is on line… You have to use your brain to know what to ask.