Grease spot on sapphire?

[Pinkmartini87]

Apologies in advance for the poor quality photos (hubby is modeling and it is hard to capture when armed with an iPhone and poor/dim evening light): I see a “spot” that resembles almost a smear on two facets, smooth to touch, does not come off with dishwater soap and a soft bristle.

Is it grease?? Or something else? This is my workhorse sapphire ring aka worn on a daily basis so in contact with lotions, toddler, etc. I do clean it nightly but these two spots don’t seem to budge. Put some more elbow grease (pun intended) into it?

How best to clean?

 

[stracci2000]

I've gotten these same weird areas on the facets of my sapphires and garnets. It seems to develop after long periods of wear.
I have searched the internet about this with no results.
And regular cleaners don't help at all.

Now, I'm not afraid to experiment with my jewelry...... so I have resorted to rubbing with a super tiny amount of baking soda paste (baking soda and water) on the tip of a wooden toothpick. You might have to scrub a little bit to see results. Avoiding the prongs, as the baking soda might scratch the metal.
Then rinse. This cleans the mark away.

Maybe someone else will offer another suggestion, but this is how I cleaned my sapphires.
Some may suggest that this mark is from firecoat, a coating that jewelers use to protect gems from heat.
But I am sure that the marks on my gems are not from firecoat, because I do not use this product when making my jewelry.

 

[ItsMainelyYou]

Baking soda should do it, it's a soft abrasive.
A yellow(the color denotes it's abrasiveness) Sunshine cloth and a good rubbing on the stone area for a minute should also work. You can use a toothpick with this as well to micro target the scrub. It will provide a tiny amount of polishing compound to the surface from the cloth.
Give it a toothbrush/Dawn bath after.

 

[Pinkmartini87]

@stracci2000 & @ItsMainelyYou

Grateful the more experienced folks have chimed in, thank you!

Sounds like it’s just “crud” buildup then? (Honestly what else could it be? It doesn’t look/feel like chips or dings or scratches to me)

I should go at it a bit more aggressively. I wasn’t sure if I would scratch the stone if I tried more abrasive methods but I suppose a sapphire being high on Mohs should be ok… @stracci2000 curious how you clean your garnets that have this same issue? Garnets are softer no? Can you still use baking soda and toothpick without fear of scratching the stone?

 

[stracci2000]

@stracci2000 & @ItsMainelyYou

Grateful the more experienced folks have chimed in, thank you!

Sounds like it’s just “crud” buildup then? (Honestly what else could it be? It doesn’t look/feel like chips or dings or scratches to me)

I should go at it a bit more aggressively. I wasn’t sure if I would scratch the stone if I tried more abrasive methods but I suppose a sapphire being high on Mohs should be ok… @stracci2000 curious how you clean your garnets that have this same issue? Garnets are softer no? Can you still use baking soda and toothpick without fear of scratching the stone?

I've done the same thing with garnets, and the baking soda does not hurt them. They are 7 on the scale.
I recently bought a dainty pink sapphire ring from a pawn shop that also had this problem, apparently from constant wear by the last owner.
I used the same process to clean it.

Also, an emerald ring from my MIL had this too. She wore it constantly.
Under the loupe, every facet had this weird rainbow-like discoloration. I cleaned it the same way, but with toothpaste, which is less abrasive. I know emerald is soft, but I was determined to get it clean. I took a big chance, but I was careful and it worked out OK.
It looked so much better afterward!

I wonder if this strange deposit is from minerals in hard water. When you wear a ring all day or 24/7, it will come in contact with water more than anything else. And if you don't carefully dab the stone off then the water stays on the stone to evaporate on its own. Thinking out loud here!

 

[stracci2000]

I went digging through my rings, and I found this sapphire with the same strange discoloration. I just cleaned this ring with warm water and Dawn, but the weirdness remains.
It is slightly iridescent. I've been seeing this on my gems for years now. It reappears after extensive wear. Surely others are seeing this too?

 

[Autumn in New England]

I went digging through my rings, and I found this sapphire with the same strange discoloration.
It is slightly iridescent. I've been seeing this on my gems for years now. It reappears after extensive wear. Surely others are seeing this too?

I've experienced this too, Stracci. I believe it is some kind of oxidation, not of the corundum, but of something on the surface reacting with the air. Because it's a bear to get off. Try using a silver polishing cloth and see if that helps. Then go over the surface with a moist paper towel to remove any chemicals the wipe may have deposited. Pretty ring, BTW!

 

[Autumn in New England]

OP, I think Stracci and Mainely have probably nailed your issue. One question - Are you certain your issue is definitely a film on the surface of the gem like Stracci's? I ask because I used to have a sapphire that, if turned in just the right direction, had rutile inclusions perpendicular to the table that would look like a oil slick. Also, conchoidal fractures can appear iridescent, and the presence of the issue near the corner of your stone (a vulnerable area) made me think of it. They can be surface-reaching or internal. But, again, it may be some sort of grim on the surface that has oxidized. Try using a silver polishing wipe, as I mentioned earlier. I normally wouldn't suggest a treated wipe, but it shouldn't hurt the corundum, as long as you wash the ring afterwards. Good luck!

 

[Autumn in New England]

I wonder if this strange deposit is from minerals in hard water. When you wear a ring all day or 24/7, it will come in contact with water more than anything else. And if you don't carefully dab the stone off then the water stays on the stone to evaporate on its own. Thinking out loud here!

This is a good theory as well!! We have hard water (and very few good hair days), and sometimes glasses come out of the dishwater with similar stains. Maybe it's oxidation of the minerals left behind?

 

[stracci2000]

I've experienced this too, Stracci. I believe it is some kind of oxidation, not of the corundum, but of something on the surface reacting with the air. Because it's a bear to get off. Try using a silver polishing cloth and see if that helps. Then go over the surface with a moist paper towel to remove any chemicals the wipe may have deposited. Pretty ring, BTW!

Yes, an oxidation issue sounds about right!
What a PITA!

 

[Daisys and Diamonds]

hard water is the bain of our exitance
the more i find out about it the more i hate it

 

[Autumn in New England]

Yes, an oxidation issue sounds about right!
What a PITA!

Hey hear me out... I'm no chemist, so this could be totally illogical. But since we 3 have experienced this phenomena with sapphire, I had a thought. Corundum is an aluminum oxide (essentially - rust), and the blues contain trace amounts of titanium along with iron. Could it be superficial oxidation of the iron as it interacts with water, oxygen, skin oils, and the like?

 

[Autumn in New England]

hard water is the bain of our exitance
the more i find out about it the more i hate it

Same!

 

[Pinkmartini87]

@stracci2000 your much clearer photo is exactly what I’m seeing with mine. So glad I asked! And super grateful you took the time to go through your treasures and take such nice photos, to help me out!

@Autumn in New England All great points, thank you! Mine does have inclusions elsewhere that come into view depending on the light/tilt, but the two smears above do not vary with light or tilt, and look exactly like the one on @stracci2000’s sapphire. She has a much better set of photos so not sure if that helps you in diagnosis—with your well trained eye, does that look like it could be anything else (internal conchoidal fracture?).

My sapphire is a bit beat up—there are minute chips/abrasions on the corners—those aren’t new however, while the smear is, and now that I look carefully I see another smear on a non-corner facet too, so I think maaaaybe more likely just yucky buildup. At least I hope! I’d hate to have an internal conchoidal fracture! (If you have a sample photo of one such fracture I’d love to see!)

 

[Autumn in New England]

@stracci2000 your much clearer photo is exactly what I’m seeing with mine. So glad I asked! And super grateful you took the time to go through your treasures and take such nice photos, to help me out!

@Autumn in New England All great points, thank you! Mine does have inclusions elsewhere that come into view depending on the light/tilt, but the two smears above do not vary with light or tilt, and look exactly like the one on @stracci2000’s sapphire. She has a much better set of photos so not sure if that helps you in diagnosis—with your well trained eye, does that look like it could be anything else (internal conchoidal fracture?).

My sapphire is a bit beat up—there are minute chips/abrasions on the corners—those aren’t new however, while the smear is, and now that I look carefully I see another smear on a non-corner facet too, so I think maaaaybe more likely just yucky buildup. At least I hope! I’d hate to have an internal conchoidal fracture! (If you have a sample photo of one such fracture I’d love to see!)

If what you're experiencing is the same as what Stracci posted, then I would rule out inclusions and fractures for sure. I have experienced what Stracci posted as well, and it is definitely something on the surface that is removable. Give the polishing wipe a try or use the methods Stracci and Mainely mentioned (I have not tried them). With a little elbow grease, it should come right off. If you're hesitant, your local jeweler should be able to assist. Let us know how you do (and don't worry... this should be an easy fix)!!