(Closed) Unsure About Moissanite

posted 4 years ago in Rings
Post # 2
393 posts
Helper bee

Disclosure: I am copying and pasting a conversation I had with other bees because it’s relevant to this board.

People often justify buying moissys because Moissanite has a Mohs scale of Hardness of 9.25 and diamond has a 10. What they fail to realise is that the ‘hardness’ really means resistance to scratching and the Mohs scale is non-linear. Corundum (rubies) is a 9 on the Mohs scale but in reality a diamond is 5 times ‘harder’.

Have you heard of people’s moissanite rings getting a grey tinge or stain on them?

The rainbow oil slick stain that occurs with many moissanites occurs when silicon carbide (what moissanite is made out of) is exposed to air and oxidises to a thin layer of silicon dioxide. This CAN occur in conjunction with, and may be enhanced by the kind of adhesive used in the cutting process, or whatever they use to mount the setting. To quote wikipedia, the rainbow-like oil-slick stain is caused by a passivation layer of silicon dioxide that forms on the surface. Nevertheless it can also occur on its own.

At one point, I too was considering asking my Fiance for a moissanite. Because they are less expensive compared to equivalent natural diamond carat weights, they are conflict free, environmentally friendly, etc.

I ALMOST feel for the advertising but then, I started digging into hard fast facts and the chemical structure, etc. What I discovered was very disappointing. I think I shouldn’t have to pay >$1000 for a synthetic gemstone that requires regular polishing and is more susceptible to scratching then a regular diamond.


Do other gemstones crack or get cloudy? Yes. Do some natural gemstones oxide? Absolutely. But it almost never happens with the same frequency as moissanite. 

I have heard of several people who have contacted Charles & Covard directly regarding this, and they were sent a cleaning cloth by C&C, and were recommended by them to  use a silver polish to clear the oil slick stains. And what does a silver polish do? It removes oxidation. Go figure.

As for the environmentally friendly spiel, most people with moissanite tend to have white-gold bands. These bands require regular rhodium plating and it’s terrible for the environment. So in all likelihood their ring isn’t environmentally friendly even if it’s a moissanite.

They don’t tell you all of this when you buy a moissanite do they?


I’m not trying to beat anyone down who has a moissy, if you love it, it’s yours and my opinions shouldn’t matter. Personally I wouldn’t ever buy a moissy for this and the reasons outlined above. 

Post # 3
9663 posts
Buzzing Beekeeper
  • Wedding: March 2014 - Chicago, IL

I have stains. Get a lab diamond.

Post # 4
1829 posts
Buzzing bee
  • Wedding: April 2018

I’ve had mine for almost a year and nothing has happened to it. I would never tell anyone to get a diamond. Get what you love. 

Post # 5
2722 posts
Sugar bee
  • Wedding: April 2017

I have a moissanite pendant and I just noticed last week that it has this oil slick.  It’s set in white gold on a white gold chain.  I noticed it when it the chain looked a little dirty (as I wear it all the time) and I used a gold cleaning cloth to clean it.  I don’t have one of those cloths from C&C so it looks like I’m going to have to get one. undecided

I’d be much more upset if this was my engagement ring.

Post # 6
1656 posts
Bumble bee
  • Wedding: July 2009

My moissy has not stained at at, but I actually give it a frequent bugg with a Sunshine Cloth (platinum setting) to keep ahead of the potential. It does not seem inevitable, as PP mentioned. Many many moissy owners have no staining and some do. Why? I understand the chemistry at hand, but not why there is so much variation. I think eventually, they will either coat them to prevent the passivation or get the base-material to actually have a depositted layer that is clear, as it done in industrial application. Keeping in mind that many commonly work gemstones come with some problems, morganite and other beryls attract oils which reduce brilliance, emeralds are incredibly fragle, sapphires/rubies are subject to becoming scratched.

Which material works for you is hard to say for us. If you have a $2k budget but want a high color over 1 carat, that won’t happen with a diamond (lab or mined), pre-owned or antique. If you have a $6k budget with the same wants, you can get your wants in both a lab or mined option. Back when my grandmother was a jeweler, it was quite common for someone to get a smaller diamond they could afford with excellent cut/light return and the upgrade that to a side-stone of a 3-stone setting or earring upon a major anniversary when funds are more available. In those days, trade-up policies were really not around, now Whiteflash and HighPerformanceDiamonds offer 100% of the value of your diamond toward an upgrade with them, provided the upgrade is $1 more. 

The environmental argument is complex and as PP said, the metal and solders used for settings come with their own harm. But, neither moissy or lab diamonds contribute to blood-wars, expect by the face that the maintain demand and that demand maintains the conflicts. With any environmental argument, there is no single answer, rather it is a weighing of which elements of the argument are more important and look at the ‘full environmetnal’ cost.  Many “green” technologies fail when put into full-cost-accounting of harms, yet people still find the carbon offset compelling. Neither is right or wrong, it is how you weight the portions of the benefit and harm.

For moissanite, the question is usually what performs most like a diamond. Here’s my list for rounds… I think the old cuts are better than modern. That said, here is how I rank the modern rounds (in order, I always prefer near colorless/GH over the higher colors for realism): NEO diamond cut, Harro Round, SuperNova (not a H&A style cut), Amora Eternity, F1 Hearts & Arrows.  For shape, rounds are more dimaond like than fancies, but I’ve been impressed with some of the cushion. The ovals look ‘too perfect’ but with the new super-ideal oval diamond being released soon, that may be less of a “tell”. Fire and Brilliance on Youtube have fantastic comparison videos (https://www.youtube.com/watch?v=Qu3MCh78Gz4).

For lab diamonds, D.Nea will sell to the public and PureGrown and Chatham sell through vendors. But, selecting a lab diamonds is exactly like selecting a natural diamond except that neither of the top grading labs will grade lab stones (GIA and AGS), so you need to be more careful with the rating outcome.

These are measurements to help you stay in ideal cut territory and apply for mined and lab.

table: 52-58
depth: 60-62.3
crown angle: 34-35.0 (up to 35.5 crown angle can sometimes work with a 40.6 pav angle)
pavilion angle: 40.5-40.9 (sometimes 41.0 if the crown angle is close to 34)

Once you find a diamond that meet these, you can use the HCA Tool to find complimentary angles. If the stone score under 2.0, request and ASET or Idealscope to see how it perforns.


Post # 7
5046 posts
Bee Keeper
  • Wedding: May 2014

View original reply
goblin :  I’ve had my OEC moissanite for 3+ years and have never had the oil slick stain. Am not sure why some get it and some don’t??

Post # 8
1584 posts
Bumble bee

I got the stain on a Forever Brilliant.  Used silver polish, took about 5 minutes and it was gone.  Really not any more “fuss” to doing that than to just cleaning it.

If you do go white gold, you will most likely need to have it “re-dipped” at some point, more often for different skin ph’s, probably water hardness, and people do that all the time without giving it a second thought.  So having to spend a little extra time to remove the oil slick stain, it’s not that big of a deal.

Now, I do believe that using a sunshine cloth ahead of time may remove that slick before it has a chance to get bigger/worse.  I think the stains that are harder to remove are harder because they weren’t noticed until they got bigger/thicker.  So, all in all, the stain is not that big of a deal.

Post # 9
1051 posts
Bumble bee

My FB is almost 11 years old. I wear it at all times: shower, workout, lotion, etc., and it still looks great and has great sparkle. Very clear, no stains or clouding or anything. I purchased through C & C.

Post # 10
1627 posts
Bumble bee
  • Wedding: July 2012

I’ve owned 7 different moissanite stones, and only one has ever had the oil slick happen (my avatar ring, 7.6mm OEC amora-ized C&C moissanite), but a good scrub down with some toothpaste and it was gone, hasn’t come back yet. 

I have a couple  14k white gold moissy pieces, but my last two were done in palladium and platinum. I’m also SUPER lazy, and don’t rhodium plate my white gold. There is a white gold/palladium alloy now that doesn’t require rhodium plating though (food for thought). 

Also, best place for lab grown diamonds: Brilliant Earth. 

Post # 11
1184 posts
Bumble bee
  • Wedding: September 2017

I’ve had my FB OEC moissanite for almost a year and no oil slicks in sight. I wear it to shower, exercise, sleep – only take it off when I’m traveling abroad for work or cleaning with chemicals, and I rarely clean it.

TBH if we had had the budget for a lab diamond I probably would have gotten one, just because of the slight moodiness of the moissanite in some lights, but overall I’m very happy with it. I got a much bigger stone than I would have been able to afford otherwise, and that allowed us to go for a platinum setting. My fiance was unsure about moissanite at first, but quickly came around when he learned about its origins in space, and of course the bang for the buck. He gets complimented on my ring from time to time, but always gives me credit because I designed it, and then starts explaining proudly how it’s not a diamond (I work in international development and am a vegeterian for environmental reasons, so a mined diamond would not be my preference unless it were an antique, which were hella expensive when we looked at those).

Post # 12
796 posts
Busy bee

View original reply
goblin :  I get oil slick from time to time. It’s not really noticable, in my opinion. You have to really look. I bought the Sunshine Polishing cloth on Amazon and it takes away any oil in a matter of seconds. 

Post # 14
384 posts
Helper bee

I’m wondering if this is common with newer stones? I used to be pretty careful with my ring- only cleaning it with distilled water and never getting it wet otherwise, because I was terrified of getting the oil slick. But for the past several months I’ve been pretty “careless”. I don’t have time to be taking it off and looking after it at work, where I work with kids and can get pretty messy. I leave it on for cooking, dishes, outdoor stuff, etc, and wash it with dish soap and tap water now. I have yet to get any type of oil slick. 

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