Yoni Eggs are typically made of semi-precious or precious gemstones. In fact, they should be, that’s the whole idea behind it, but you can also buy them made of silicone, glass, wood, or hard plastics.
Nevertheless, you may want to opt for a gemstone alternative, because one of the health risks is that even the toughest eggs are porous (or somewhat porous, depending on the type of gemstone) and can hold bacteria.
It means that it’s not always possible to really, completely clean the egg in between each use. This can cause infections. In any case, below a brief discussion of the alternatives for Yoni Eggs made of gemstones i.e. crystals.
Glass
Glass perhaps doesn’t have the special mineral properties of gemstones, but it’s very safe for the body and most of the times completely nonporous (do mind that porous glass also exists).
As such, glass Yoni Eggs are in fact safer than traditional stone or crystal eggs when it comes to cleanliness; harmful bacteria and other pathogens can be removed much easier. You can find glass eggs in a variety of colors.
Glass Yoni Eggs are typically made of Borosilicate glass, which is highly resistant to thermal stress and can withstand temperature differences of about 165 °C without breaking. It’s a glass type often used for the construction of reagent flasks, for lighting, electronics, optics, and cookware, among other applications.
Wood
It sounds perhaps somewhat strange, but it’s also possible to use wooden Yoni Eggs. Notably Mantak Chia describes the use of those in his book Healing Love through the Tao: Cultivating Female Sexual Energy.
Of course, extra hygiene and safety rules apply here, notably when it comes to bacterial infections, peels, and splinters.
Wooden Yoni Eggs should always be boiled before use, preferably in a diluted vinegar solution. After cleaning the egg it needs to dry for about an hour before using it.
Plastic and Silicone
You can find silicone or plastics Yoni Eggs on the market sold as being actual gemstone Yoni Eggs. Thus, make sure to only buy from a trusted Yoni Egg provider, one who has a rigorous certification procedure in place.
Another case of silicone (or plastic) “Yoni Eggs” are Yoni Egg-like products (often with other shapes than a Yoni Egg) of which it’s claimed to have the same benefits as stone or crystal Yoni Eggs. This may be partly true, and for a range of exercises it doesn’t really matter, but then again, synthetic materials are never exactly the same as natural products.