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Hello IGS Members,

I am new to this group, joined just a week or two ago. I posted two questions about gem identification and saw quite a few had looked at my posts, but, at least last time I checked, I had 0 responses. I wanted to let everyone know that I am working all the time, and rarely have time to go on-line for my own personal interests. I work as a therapist, but grew up in the countryside of PA, where I escaped my troubled family for the safety and wonder of the fields, woods,
the streams and ponds, and the rocks and all the life forms to be found. I loved checking out the beautiful salamanders under the rocks on the streams’ edge, and imagining the sparkling pyrite I’d discovered was real gold. It feels so good to be reconnecting with the gem, mineral and fossil finding that kept me sane as a kid, and it’s so prevalent here in Colorado, I can’t get over it. I can pick up a rock in my backyard and it’s almost always something of interest. I hope that now that I’ve had a moment, albeit at past midnight, to properly introduce myself, maybe some of you will do the same and consider lending your expertise to my two earlier posts with Gem ID questions. I’m also curious if anyone is familiar with Saffordites (AKA: Cintamani Stone)? If so, please message me. Thank you!
Hinde, PS: Still learning the ropes on here, so feel free to lmk if I’m doing anything wrong and not aware.


i am a newby to, i am 64 yrs young and have just started to learn about gems, i am never to old to learn, lol i live on a remote Scottish island and am trying to learn as much as i can.

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Well hello there and thank you for reaching out. I agree that the only people who truly grow old are the ones who stop learning! I’ve always wanted to see Scotland and the surrounding areas. Were you born and raised on the island you currently reside on? Have you ever been to the United States? I was born in the USA, in DelRay Beach, Florida but my parents moved to Pennsylvania when my mom got pregnant with my brother who was only 15 months younger than me, so I don’t remember FL at all. Do you find interesting rocks on your island? Back to work I go. So nice to hear from you and I hope you will keep in touch. Hinde

I don’t think there is a wrong question, but there are questions that can’t be answered on line in a few words. Looking at the found rocks you have discovered, I think you need to learn the basics of rock and mineral identification. So some elementary books on the subject from the library, or maybe some on line sites with similar material would help. Rocks and minerals are often weathered and not particularly distinctive in appearance and there are look-alikes. Photos will help identify some minerals and rocks, but you also need points or tools to measure hardness…things as simple as a fingernail, a copper penny, a steel nail, a known piece of quartz and a known synthetic corundum would be starters…books will give you other ideas. Then a small scale and cup of water for determining specific gravity. A good loupe or magnifying glass. A rock and mineral book will give other ideas. It would be nice if you could get all your questions answered here, but I can’t do a hardness test or SG determination over the internet. Good luck!

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Since 1982 copper pennies are copper-plated zinc. Do they still work in hardness testing or do you need to dig into the piggybank and find an older one?

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where in Pa?? I am from the western woods of pa. also a learner of faceting. bumping along.

Hi there Ken, I am from Selinsgrove, I guess it’s more Central PA, are you familiar with that little town? Susquehanna River is there, and Susquehanna university. How’s it going learning faceting?

Hi there Roy or perhaps, John?
Thank you for your message. I realize it
is difficult to properly identify/authenticate a
rock or mineral on the basis of just one or two photos.
I think sometimes I get so excited and am seeking
validation of what I have already identified and
letting my passion cloud my vision so to speak.
I have a question that I can’t find the answer to.
When I measure specific gravity, how submerged
does the attached specimen have to be under the water.
I don’t let it touch the sides or the bottom, but I’ve noticed
the data changes quite dramatically depending on how far
down I allow it to sink. Any thoughts on this? I really appreciate
any help and your list of items is validating as well, showing me I have
been doing all the right things as I reconnect with this new world of rocks,
some similarities but very different from PA “old mountain” geology.
The one thing I am missing in my “toolkit” is a Moh’s hardness testing kit.
I look forward to hearing back if you have some insight into my question about
measuring SG. Also, on that same topic, my understanding is you measure the
stone in question in grams, (I have a small electric scale for this) and then take a lightweight cup and fill it with water, place it on the scale and press “tare” to zero it out, then I lower the stone in, I use dental floss to rig a makeshift “harness” for the item and then this is the part I need your help with, how far down should it go, am I trying to center it? And then to determine SG, you divide the first measurement of the rock by itself by the second number you obtain when the stone displaces the water. The answer is the SG of that specimen. Is this correct? I read something different recently and it has confused me. Thank you in advance for your help and encouragement of a new member. Please note that I work a lot and so it might take me a bit to respond but please be patient, as I will be with you, and I look forward to your response when you are able. Have a great rest of your week and wonderful weekend, H.

Good question, azeller, I’m following, hoping someone will answer.

Hello Hinde,

You must submerge the stone totally in the water…you are measuring the weight of the water

displaced by the stone. You measure the weight of the stone most easily by resting it on the

bottom of the container of water. So just tare out the water container, then suspend the stone

in the water totally submerged, note that measurement, then take another measurement with

the stone resting on the bottom of the container (string slack). Weight of the stone over the

weight of the water displaced (bigger number over smaller) gives the SG, which is always

greater than 1. Yes, using the lightest string or dental floss will give the most accurate

measurement. Measure some quartz or other stone that has a rather invariant SG to see

how close you are getting.

You can buy a set of hardness points, but you can also cobble together a set. Here’s a link

as to how to do hardness tests:

Fingernail is 2.5, copper penny is 3, flourite crystal you can buy off a kid’s mineral display in

tourist stops is 4, a steel knife is about 5, orthoclase is 6, quartz is 7, and a piece of synthetic

corundum is 9. A topaz crystal would be 8, or a piece of aquamarine. Most of this should be

pretty cheap to find. If you have other known minerals, they may do fine.

If you get into gems, a dichroscope, a polariscope and a standard magnet for magnetism

tests will be helpful, as well as a copy of Gem ID Made Easy by Matlins. There is a free

gemology course by Barbara Smigel on line…some of that would be applicable to minerals,

too. I would guess that there are mineralogy courses on line, too, but IDK exactly where,

you would just have to look. If you are looking for an actual certificate in gemology, the IGS

is one and GIA (pricey!) is another.

Have fun!

royjohn (that’s my screen name)

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Thank you so much for the instructions
on obtaining SG.

I have a magnet and I also use a UV light
to assist with authenticating.
Thank you so much for the helpful links
and for recommending Barbara Smigel’s
free online course, looking forward to it,
what a generous offering!

Have a great rest of your day,
my head is starting to pound…
long day…

Have a good evening,


Hello, welcome to the wonderful world of stones. IGS has a great set of courses for gemstones. If you are just doing some rock hounding, you may find a local community to lear with and from. A lot of these groups do get together to go into the field and hunt for rocks.
You are never too old to start learning and having fun.
All the best,

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I wanted to share with you that I solved the
story of the mystery rock. I’m still not getting an exact
and correct SG, (I kept coming up with 1.7, no matter what the stone), however I sadly discovered that what I had thought and hoped, was sapphire, is actually copal crystal, and the other stuff I’ve been finding a lot of and also confused with sapphire is chrysoberyl, some of that is pretty neat, it changes color like alexandrite, and a also have a few that display chatoyancy, so that’s nice. Just thought I’d share my findings, and thank you again for the solid advice and support. Have a great week!

I’m not sure about that, did you ever get an answer? On the pennies?

No answer. Again, do the new pennies of copper-coated zinc still work as a hardness tester?