gem ID please

not sure what this is. it could be a black garnet or just a stone? weighs 2.1g

My first guess would be a sapphire though it's fairly worn. Have you done a scratch test with it to see if it cuts glass?

Hi nero, havent done any tests yet. i found it with these these other round stones and am thinking it might be garnet. very new to all this and being looking at images of gems until my eyes bleed trying to do identifications on stones i find whilst panning for gold.

sorry abut the blurry phone pics. i will have to get a macro lens for my cam i think.

well it certainly does scratch glass so yeah maybe thats it.

russ

I agree with Nero it could be sapphire, Most any hard stone and even quartz can scratch glass, a better test would be a steel scribe, even a file wouldn't touch a sapphire , which is corundum at 9 on the hardness scale only a diamond at 10 is harder but keep in mind a sapphire could chip or fracture, often you will see existing fractures on the surface and they can look like half moons . cleavage lines, it looks like you have some on that stone on the left side in your picture, another way is check the specific gravity as sapphire is many times heaver than both quartz and garnet.
Clues for identifying gemstones are location found, color, hardness, weight, transparency, fracture cleavage, and then even sometimes the experts get it wrong
Cheers Mark

hi ms
i could be wrong but i thought that hardness scale (mohs or something like that) was just for
natural things, in other words manmade things like some steel can damage/break even diamonds at 10
on the scale
cheers

thanks for the info. looks like i should find a local club to help identify them. i have a uncle a couple hours away who used to live and mine out at rubyvale for about 5 years so i should drop in and see him.

That way at least i can go back and get lots more if they are genuine gem stones. would hate to dig up bucket fulls of stones not worth the trouble. but i do know this particlar area i was known for topaz, quartz crystals, gold, sapphires. I was just hoping for gold instead.

there is never anyone there accept for bloody flies!

there must have been a fly population explosion or something because i havent ever seen it like that bad before. these flies stuck to the side of the car in mass and made it look like i had a black sided car. the moment you open the car door its like 50 million flies just swarm inside the car. even tried to out run them when leaving and i can tell you these flies were still coming in the window at 40KM/hr! lol

I had to get a fair speed up with all windows down to suck them all out.

anyhow as it gets cooler it should be better

russ

fencejumper wrote:hi ms
i could be wrong but i thought that hardness scale (mohs or something like that) was just for
natural things, in other words manmade things like some steel can damage/break even diamonds at 10
on the scale
cheers

Hi fencejumper- Yes the mohs scale does use natural materials to indicate the hardness scale as it was found hundreds of years ago and thats all they had to use, it's not a proportional scale and when your see Sapphire is a 9 on the hardness scale and diamond is 10 , diamond in fact is many times over harder than a sapphire at 9, you will be able to scratch with anything at or above the same hardness level, ie sapphire will scratch sapphire and diamond will scratch diamond, but the key word here is scratch, a hammer on steel will smash a diamond to bits,{Fracture}
If you do a scratch test with a hardened scribe point or even a file , scratch test don't try rasp into the test piece as you may fracture the material
Mark

hi razgo,
have done a bit of gem stuff in the past,if this has come out of heavy gem wash then it possibly will be onyx...all the black ones I got with my sapphires turned out to be onyx according to an old time sapphire miner...you would need to know where it actually came from... cheers SS

put a strong light to the back of it !! you will know if it is a gem if it has colour

secret squirrel wrote:hi razgo,
have done a bit of gem stuff in the past,if this has come out of heavy gem wash then it possibly will be onyx...all the black ones I got with my sapphires turned out to be onyx according to an old time sapphire miner...you would need to know where it actually came from... cheers SS

hi squirrel, i know where it came from because i got ot from the creek i was fossicking in just not revealing the location as i am still fossicking and detecting the area. but i do know historically the area is known for topaz, quartz crystals, gold, sapphires. i never thought about onyx.

shinning a light behind it didnt reveal any clours that i could see.

mate...i recon it could be onyx as you will get no light passing through.....if you use a strong light under a sheet of cardboard with a pin hole in it(place the gem on top of the hole) then you can get a better concentrated light beam....keep all the bigger ones you find
they do use them in jewelery.. hardness is 7, specific gravity about 2.66...you could try to calculate this yourself but you don't have much weight in this little stone and would need some very accurate scales to weigh in and out of water for the calculation.....weigh in carat for accuracy...if you find anymore then keep a look out for bands of color in them, they do occur as well....
cheers SS

well i dont know how to weigh in water. never tried it before. the scales i used to weigh are 0.001g accuracy up to 10g. it weighed 2.12g but i dont know how to weigh specific gravity.

do larger onyx stone retain that really dark black colour? i have a much larger one but looks more like an ordinary stone as it's not as black and was from another area.

i tried the pin hole light technic and yes no light coming through at all.

If i do find a lot more of these i will have to take them somewhere to be looked at i guess to check out exactly what i have. As who knows, what i found might be all there is until i go back again and spend more time in the area.

I found the round egg shaped one very interesting.

i guess these products would be useful out in the field? http://www.mineralab.com/Gem%20ID.htm

russ

hi
cover the sun with your hand and hold the stone on the edge of your hand. move your hand so the stone is covering the sun. do you see colour through it?

If it only panned out to be a 10ct Royal blue saph. Whoopy....

Cheers kon61.

To check the sg you might need a scale with a greater range but same accuracy as 0.001gm.

get a small light container and put in enough water to fully cover the stone without it resting on the bottom of the container.
First measure the dry weight and then with the container of water on the scale pan, tare the scale to zero.
Then tie a thin cotton thread around the stone and make it long enough to hold the stone fully emersed and suspended in the container of water by your fingers. Do not let any part of the cotton or stone touch any part of the container. The scale will now read the LOSS OF WEIGHT OF THE STONE IN WATER.
Divide this figure into the dry weight and the result is the SG of the stone.
Be sure there are no bubbles on the stone while suspended in the water.

The SG of Saphire is 4.0, Quartz = 2.65, Onyx = 2.58 to 2.64

if you need to dry weigh it again for any reason after the first in water weighing then be sure to dry the stone first.

hi adrian
when you do the weighing in water, dont you tare a stick or wire on the scales then hang the stone of it into water?
or is stones done differantly to gold
cheers

100% correct you have to take into account the weight of the suspension but in this case a piece of cotton is not going to affect the result much. When testing small stones say 1 gm or less then it would be a good idea to tare the scale with the suspension (that part that goes into the water) before doing the wet weight.

If you use a scale that is 0.01 or 0.1gm accuracy then the result will be a ball park figure for small stones. The suspension needs to be as light as you can possibly get. But if the scale is not capable of measuring (not sensitive enough ) the weight of the suspension then there is likely not much point in trying to tare the scale with the suspension fitted because the scale won't respond to it.

So put simply; If the scale can read the weight of the suspension (only the bit that goes in the water) then you should tare the scale to the suspension prior to doing the in water loss of weight check.

If the weight/density of the item being tested is many times that of the suspension then the less the suspension will effect the test result. For very heavy items like large rocks and boulders that weigh a few kilos or more a set of kitchen scales will give good enough results even if the suspension is a bit of coat hanger wire. When measuring small stone of a gm or less it is a good idea to take several readings and then work out the average if your scale is in the 0.01 to 0.1 gm accuracy range. Idealy you need to be able to measure the weight to 3 decimal places or better.
Also you will need to keep any draughts from blowing on the scale when testing small stones with high accuracy scales.

I called into my uncle's place yesterday and he says its a cumick(spell?) i think he worded it. appaernetly it's the stage before it becomes sahpire.

russ

yes about 6000 deg before

Razgo wrote:I called into my uncle's place yesterday and he says its a cumick(spell?) i think he worded it. appaernetly it's the stage before it becomes sahpire.

russ

hi russ
if that's what it is, are there any use's for that stuff? can it be cut?
i've never heard of it before
cheers

good question, i actualy don't know. But i will find out more. I have to get the correct word/spelling first. he described it as when the volcano first spews it up thats what you get is this dark black molten stone which eventually turns into sapphire.

I will find out more this week.

russ

Razgo wrote:good question, i actualy don't know. But i will find out more. I have to get the correct word/spelling first. he described it as when the volcano first spews it up thats what you get is this dark black molten stone which eventually turns into sapphire.

I will find out more this week.

russ

hey Russ
this might bring you a bit closer:

Rubies and sapphires are derived from Corundum or Aluminum Oxide, a mineral running second only to diamond as the hardest natural mineral in existence. Volcanic processes in the depths of the earth by the metamorphic processes used to transfer high heat and high-pressure into crystalline forms form this mineral. These Aluminum Oxide crystals alone are clear and only when impurities enter the rock during the recrystallization process do they form the traditional precious stones rubies and sapphires. Corundum comes in a variety of colors and depending on the translucence of the crystal-field can be highly valuable.

Sapphires are formed when small amounts of titanium and iron seep into the cooling Aluminum Oxide. These blue gemstones come in a range of shades, from pale, icy blue to a deeper cobalt color. Sapphires can also be orange-pink, purple, green, white, golden and black, depending on traces of other elements.

cheers SS

Ps..I still think it might be Onyx...it'll polish up nicely for a ring..

My money is on corundum or spinel based on the many similar pieces i have sieved.
Tributer

ah thats it! thanks SS, yes the word i was looking for was Corundum. well that was the first thing he said when he looked at it.

I have yet to specific gravity weigh it when i get some scales.

russ

Razgo wrote:I called into my uncle's place yesterday and he says its a cumick(spell?) i think he worded it. appaernetly it's the stage before it becomes sahpire.

russ

yout wrong buddy its spelled Corundum lol.

Razgo wrote:not sure what this is. it could be a black garnet or just a stone? weighs 2.1g

Looks like black tourmaline aka schorl.