Thread: The La Veinette at 500X looks like a bed of quartz shards.

The Stone is a bed of quartz front and back and is natural, FAST, yet fine, the BBW is quartz too, I was shocked to see that, have any of you seen that in a coticule?

I looked and searched for garnets, when I dropped down to 45 power and you could see what appeared to be garnets, stained quartz I'm thinking.

I wonder if there has ever been a study of Coticules with the electron microscope??

Magnet test the slurry.

Garnets are magnetic and will stick to a strong magnet like a rare earth neodymium, It's one of the few gems that is pretty easy to classify because of this.

They also don't have to be red. They have a range of colours from yellow to blue, and a range of levels of clarity.

With a decent magnet you should be able to get the gems to raise to the top of the slurry, and perhaps get the slurry to follow the magnet a little.

This should have enough force to show you if it is garnet or not.

http://www.first4magnets.com/hook-ey...4kg-pull-p3828

Or one of these if you have the strength to remove it from whatever you store it on! 90kg's on such a small area will be a pretty dangerous magnet in all fairness. You wouldn't want to trap a finger with that much pull.

http://www.first4magnets.com/hook-ey...0kg-pull-p9072

Cool, I have some Neo magnets, Thank you Iceni, will give them a try.

Post back your results as I've only ever seen this with bigger garnet. It should work on the fine grade stuff as well as it's one of the methods used to separate garnet from sand for grading in abrasive production.

It will depend on the iron content of the Garnet. Most Garnets are not susceptible to magnetism. Most garnets are processed using a gravity system. A small percentage are processed using magnetic separation.

I wouldn't be using magnetism as a primary or secondary way to identify garnets. Often times when you get a strong magnetic response it's other minerals mixed in that will give you that response. You need have clean xtls for the magnetic test so you know that there is no cross contamination giving you a false positive.

Usually garnets are pretty distinctive looking so in most cases you can identify them by sight. Figuring out the variety (and there are many) is another story.

There are a few garnet types that don't have strong magnetism. Most do, as such it's a pretty good and non destructive/specialist equipment test. I agree it won't tell you exactly what the gems are, But it would clear up the Quartz argument. As very few Quartz's (without inclusions) are magnetic, You'd have to be dealing with something like bloodstone. And that stuff is dark green with red spots so it would look visually different in a 30-40% content stone.

http://www.gemstonemagnetism.com/upl...or_Website.pdf

Originally Posted by FAL

I wonder if there has ever been a study of Coticules with the electron microscope??

Hey Fal,

Yes there were sime pictures done, no real study but pics:

Slurry from a Coticule at 2600x


https://flic.kr/p/kkSmrF

Coticule Surface at 5000x

https://flic.kr/p/kkSm2H

Garnets are magnetic! Damn! My "steel-powder - spared slurry separator'' is screwing me up, indeed! Some useless creamy mud it saves!