Is coloured moissanite coated? Black, blue and pink moissanite

Quick answerUpdated October 17, 2026

Some coloured moissanite is coated. A 2024 study in GIA’s journal Gems & Gemology found thin coatings on pink and light greenish-blue moissanite (gold nanoparticles on the pink, silica tinted with metals on the blue), and its authors note that most producers and sellers claim their stones are not coated. A coating can scratch and wear at facet edges, so ask the seller and keep coloured stones out of ultrasonic cleaners.

What did a 2024 study in GIA’s journal find on pink and blue moissanite?

In the Spring 2024 issue of GIA’s journal Gems & Gemology, researchers in Taiwan examined five synthetic moissanites bought in 2020 from one supplier, which sourced them from a growth facility in Guangxi, China: two pink, two light greenish-blue and one colourless stone for comparison, described as typical of the stones their laboratory saw. When the coloured stones were sawn apart, the colour sat at the outer edge and the centre was colourless: they were coated on every facet. The blue ones carried a film of silica (silicon dioxide) about 45 and 62 nanometres thick, containing vanadium, manganese and cobalt, which the authors took to be the colouring agents. The pink stone they analysed most closely carried a gold-bearing layer under 20 nanometres thick, gold nanoparticles set in silica, over an even thinner film of . The authors note that when gem laboratories receive coloured moissanite, “most producers and sellers claim they are not coated”. They describe a pink stone whose seller insisted the colour was not from a coating; under the microscope its colour was unevenly spread over the surface, a sign of a coating. Four coloured stones is a small sample, so this does not prove that every pink or blue moissanite is coated. It does match earlier reports. In 2018 the French Gemmological Laboratory (LFG) in Paris found that a 0.41 ct pink stone resembling a pink diamond was moissanite under a calcium-rich film coloured by iron and titanium, the first coated moissanite it had seen. In 2023 the Gemmological Association of Australia described twenty surface-coated moissanites it had bought for its teaching collection, and said such stones were sold in over twenty colours on multiple websites.

Which moissanite colours are grown in and which are coated?

Moissanite can take colour as it grows. The 2024 authors note that the cubic form of silicon carbide is yellow, and that adding nitrogen or aluminium during growth gives colours such as light brown, green and deep blue. They add that doping had not yet produced the light blue and pink seen in coloured diamonds, although they also cite a 2017 report from GIA’s laboratory of a light greenish-blue moissanite coloured through the crystal itself. The Australian article says coloured moissanite was long limited to tones of brown, green, light blue, teal and black, and that brighter blues and yellows, pinks and reds arrived only recently, with surface coatings. Colour from growth runs through the crystal. A coating is a film on the surface: the stones sawn apart in the 2024 study were colourless in the centre.

Colour on the listing	Can growth give it?	What the studies found	What to do
Yellow, champagne, light brown	Yes	Brighter yellows arrived with coatings; a coated yellow-brown stone in the Australian article showed a strong golden colour on its back facets	Ask whether the colour is grown in
Green, teal, deep blue	Yes for green and deep blue	Green and teal were on sale for years before coated stones appeared	Ask whether the colour is grown in
Light blue, light greenish-blue	Sometimes: GIA’s laboratory reported a grown-in light greenish-blue in 2017	Both light greenish-blue stones in the 2024 study had a coloured silica coating	Ask, and get the answer in writing
Bright blue	Not reported in these studies	Brighter blues arrived with coatings; the coated blue stones in the Australian article showed a metallic sheen with purple, green and blue reflections	Assume coated unless the seller says otherwise in writing
Pink and red	Not pink, according to the 2024 authors	Every pink stone in all three reports was coated: gold nanoparticles (2024), a calcium-rich film (Paris, 2018), a mottled, sputtered-looking coating (Australia, 2023)	Assume coated unless the seller says otherwise in writing
“Mystic” iridescent colours	Not reported	Sold in the range of coated stones the Australian article describes, which compares their coatings with those used on topaz, as in mystic topaz	Treat as coated; handle as you would mystic topaz
Black	Not covered by these studies	On sale before coated colours appeared, but none of these studies tested a black stone	Ask the seller

Does coloured moissanite fade or wear off?

Colour grown into the crystal runs all the way through, so wear cannot rub it off. A coating can wear. Moissanite itself is hard, 9.25 on the scale, but GIA warns that thin-film coatings of any kind are prone to scratching, especially along facet edges and junctions. Every coated stone in the Australian article showed fine scratches in the coating and some loss of coating at the facet edges, and where the damage was worse a loss of colour could be seen with a hand lens; on the Paris stone, scratches in the film left the colour uneven. The 2024 authors expected the coatings to be durable under normal circumstances and found the blue silica film chemically stable and unlikely to peel, but warned that gold-nanoparticle coatings can come away under mechanical or thermal stress. None of these studies tested fading in sunlight; the damage they describe is wear. To check a loose stone, look at the back facets under a loupe in reflected light: a metallic lustre, a bronze or golden sheen, patches or flakes, mottled or uneven colour, fine scratches or worn facet edges all point to a coating. The Australian stones were coated on the back (the pavilion) only, so nothing showed through the top, which makes a set stone hard to check. Doubled facet edges show that a stone is moissanite, not whether it is coated; see does moissanite pass a diamond tester?

What does black moissanite mean, and is it coated?

Black moissanite is moissanite, lab-grown silicon carbide, in black. The name describes the material and the colour, nothing more. It is a different material from black diamond, and the 2024 Gems & Gemology paper mentions a case of black moissanite used to imitate black diamond. Black was among the colours on sale before coated moissanite appeared, according to the Australian article, but none of the studies on this page tested a black stone, so we cannot say how the black moissanite sold today is coloured. Ask the seller whether the colour is grown in or a coating, and keep the answer in writing.

How do you look after coloured moissanite, and what should you ask the seller?

Clean it with mild soap, warm water and a soft toothbrush. Charles & Colvard, a moissanite maker, advises against harsh chemicals and ultrasonic cleaners for its moissanite, and that matters more for a stone that may be coated. GIA advises keeping hard or abrasive objects away from coated gems and storing them wrapped in soft packaging in a dry place when not worn, so keep a coloured ring apart from your other jewellery. Before any repair that heats the setting, tell the jeweller the stone may be coated, since the 2024 authors warn that thermal stress can lift a gold-nanoparticle coating. Before you buy, ask whether the colour is grown in or a coating. In the US, the FTC Jewelry Guides say a seller should disclose a gemstone treatment that may not be permanent or that creates special care requirements, and for online sales that disclosure belongs in the product description (16 CFR 23.24). A GRA card does not settle the question: the GRA reports with the Australian stones named them as moissanite but did not mention the coating. See is a GRA certificate real? and gem treatments explained.

Frequently Asked Questions

Is pink moissanite coated?

Every pink stone in the reports cited here was. The authors of the 2024 study say doping had not yet produced pink moissanite and found coatings on both pink stones they examined, and the pink stones in the 2018 Paris report and the 2023 Australian article were coated too. Ask the seller, and treat an unexplained pink as coated.

Does coloured moissanite fade?

Colour grown into the crystal runs all the way through, so wear cannot remove it. A coating can scratch and wear thin at the facet edges, which shows as patchy or paler colour. None of the studies cited here tested fading in sunlight.

Is champagne or yellow moissanite coated?

It can be either. Yellow and light brown can come from growth, but brighter yellows have appeared with coatings, and the Australian article describes a coated yellow-brown stone. Ask the seller whether the colour is grown in.

Can the coating be removed?

Not by cleaning at home. The authors of the 2024 study say removing the coloured coatings completely would mean polishing the whole stone, and the stones they cut apart were colourless in the centre under the coating.

Sources

Keep reading

Amazon links are affiliate links (tag thegemtray-20): buying through them costs you nothing extra and supports the site. As an Amazon Associate we earn from qualifying purchases.