Do Vedic Gemstones Need to Be Unheated?

Ruby, blue sapphire and yellow sapphire should all be unheated for Jyotish, Vedic astrology. Emerald is never heated, but it is oiled: virtually all emeralds are treated with some type of oil or resin, and minor treatment is OK.

Most sapphires and rubies sold today have been heated to improve their color or clarity. With certain gemstones, it is absolutely critical that they be free of treatments or enhancements. In other cases, it is almost impossible to avoid some kind of treatment.

Ruby: unheated, and why we changed

Ruby is the one stone where our view changed. We used to sell heated rubies for Jyotish, because the Sun is a hot planet and can handle heat. But heating does alter a ruby’s chemical structure. Over about ten years, we noticed that the number one stone we had long-term buyback requests for was heated ruby, followed by heated white sapphire. So we stopped selling both because of those results.

Every ruby we sell today is unheated. Avoid the other ruby treatments too: beryllium diffusion, lead-glass filling (these rubies are poor quality, heavily treated and unstable), and glass-filled cavities on the back of the gem.

Blue sapphire: never heated

Blue sapphires, in particular, should never be heat-treated. Saturn is a cool planet and doesn’t take heat well, and the Garuda Purana, a Vedic scripture on the astrological use of gems, warns against heated blue sapphire.

It is very important for Saturn gems to be eye flawless and not heated, and the more flawless the better. Minor rutile silk is fine. Silk can be a good sign, but seeing silk in a photograph doesn’t prove a sapphire is unheated; the lab report does.

Yellow sapphire: unheated

Yellow sapphires should be unheated too. Regular heat treatment frequently turns these gems a more golden to orange color, and beryllium diffusion is another heat treatment to avoid. As with ruby and blue sapphire, heat changes the stone itself, and in Vedic Gemology we consider these treatments to permanently alter the gem’s energetic properties. Unheated yellow sapphire from Sri Lanka (Ceylon), of top clarity and fine lemon yellow color, is most desirable.

Emerald: never heated, but oiled

Emeralds are never heated, but all emeralds are treated with some type of oil or resin to help stabilize the gem, fill in the cracks, and diminish visibility of the flaws. It’s virtually impossible to find emeralds that have not been treated in this way.

While the traditional way of oiling emeralds was with cedar oil, the industry standard is now a treatment called ExCel, a type of resin that lasts much longer. Cedar oil needs to be redone every few years.

It’s best to look for emeralds that are nearly flawless, with an absolute minimum of inclusions or cracks; then the oil will have the least effect. If there are no cracks at all, the oil will have no effect whatsoever. The clarity and flawlessness of emeralds is what’s most important, not whether they are oiled or not. Avoid heavily treated emeralds. Some experts can grade the level of treatment as minor, moderate or heavy, and minor treatment is OK.

Citrine and tourmaline: heated at low temperatures

Citrine and tourmaline are usually heated too, but heat works differently in them. Natural citrine is usually heated in the earth before it’s even mined. We suspect heat inhibits their power to some extent, but labs can’t detect it, because it doesn’t change the stone’s chemical structure, and as such we have reason to believe their Jyotish properties aren’t eradicated. That is the line between them and ruby or sapphire, where heat does change the structure.

The other treatments to watch for

• Pearl: AGTA requires us to disclose bleaching as a treatment on imported pearls. That usually means the pearl was sanitized with hydrogen peroxide, so “bleached” depends on context; ask the seller what was done.
• Red coral: should be undyed. Dyed coral is common in India and elsewhere, and so is plastic-filled coral. Also avoid uneven color, cracks, black pits and fractures.
• Diamond: should be natural and untreated, and not lab-grown.
• Hessonite: generally never treated. It should be as clean as possible.
• Cat’s eye: increasingly irradiated these days, to produce slightly different colors such as a strong yellow or a silvery gray. The natural color is a greenish yellow. A “milk and honey” cat’s eye is desirable, and in many cases the price will tell you whether it’s natural or not.

How to tell whether your stone has been heated

You can’t tell from a photograph, and most buyers can’t tell with a loupe. Your best protection is the source. Buy gems from someone you know to be knowledgeable and trustworthy. If the price seems too good to be true, there probably is something wrong that you are missing. Shop and compare quality, and get expert advice if needed.

The second protection is an independent laboratory report, which states whether the lab found evidence of heating. Read how to read a gemstone certificate here. Read which gemstone certificates you can trust here.

Heat can also reach a stone after it’s bought, if a jeweler works with a torch near it while setting, sizing or repairing the jewelry. When we set a gemstone, it is never exposed to heat.

What this means when you buy

Every stone we sell is natural, and its treatment is disclosed on its page. If a gem you buy from us is certified by a reputable lab with an identification or treatment other than what we disclosed, we refund the sale as soon as it’s verified.

Not sure which gem is yours? Start with our Free Gem Report. If you’re ready to buy, order a Personal Consultation to confirm the gem is the right match for you. The consultation fee is credited back with any gemstone purchase over $500.