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Question about unknown RI Fluid


I recently purchased an RI Fluid from mineralab on Amazon (brand, Gem-a), and I was wondering if anyone can assist me since I’m new to buying RI liquid all together. the seller hasn’t gotten back to me yet, and I want to verify its toxicity levels. It does say it’s toxic, but I don’t know if it’s “paint” toxic, or “Chernobyl” toxic. It also says to use in a “well-ventilated” room, but that’s vague; would an average sized living room with 2 open windows be enough, or would I need more?

RI Fluid information:
nd. 1.78 - 1.79 (= or < 25C)


I see that there’s a review where someone wrote that the toxic fumes “bother his sense of smell”, indicating he didn’t use a strong mask, or perhaps didn’t use one at all. Still, I want to be cautious about something that’s toxic. Can anyone provide any extra information?


You should at least follow these specific safety recommendations when using toxic RI fluids. You can also find some general safety recommendations here.

As for what constitutes a “well-ventilated” room, this article by Charles Lewton-Brain covers the topic pretty well. I would caution you against using RI fluids in what is actually your living room, especially if you have any children or pets.

We have a list of the properties and formulas of chemicals commonly used for RI fluids, but we don’t have information on the specific fluid you purchased. If you hear back about this fluid’s specific composition, let us know.


I purchase my ri fkuid from Cargill. They have the best quality and price. It is lab quality and they sell many types for many things. The tyoe i buy is specfically for gems and it us as safe as it comes.


It looks like the Gem-A brand is manufactured by Cargille Labs. You can find their Material Safety Data Sheet here: Diiodomethane MSDS

To answer your question about ventilation, the conditions of intended use specify 5 air changes per hour.

Look at the first aid measures in section 4 as well. These may give you an idea of its toxicity.

I hope this helps.


Gem-A is the British version of the GIA. There RI fluid works well. I have used it many times as well as Cargill. I do use it at my table which is a few feet from a window. I usually keep the top cracked open. I also gave a small air purifier nearby. So far my dogs don’t mind it; but I keep them out of my work space.


I’ve used it for years, from serval sources and of course, be careful but you wont have problems with RI fluids in most cases. Don’t breathe it directly for long periods, wash your hands after using it, don’t sniff the open bottle. Clean your work area after using, but its still one of the best investments for testing.


It IS toxic… like any chemical, use gloves, or wash your hands after touching. Do not touch your eyes, mouth while using it…and do not breathe it for long periods of time without ventilation.

Store it away from pets or children.

It won’t blow up, but it isn’t good for you either…


The GIA have completely ditched the Cargill brand RI Fluid, for a much lower-toxicity RI fluid manufactured by Gemmaster. If you’re in the USA contact Raymond Mason in Arizona who is the US distributor.


It is toxic, but I have used both 1.78 and 1.81 for years and years (45 to be exact). No gloves, no mask, no nothing…however wash your hands afterwards. Don’t breath directly from the bottle. Clean your work area afterward. I have my office in a professional building, so there are no open windows. My personal feeling is that while there is good reason to be aware of how toxic a substance is, sometimes the warning labels are a bit overkill.


Too the 45 year young old school I loved your response personally health and safety are way over the top I’m 52 and pretty soon you’ll see people wearing gloves at lunch lol.