There must surely be as many different styles of vintage engagement rings as there are engagements and proposals! The classic, of course, is the diamond solitaire. Usually seen in a traditional claw setting, with the number of claws holding the diamond being anything from four to 12, the solitaire diamond can also be rub-over set. Either way, the traditional band is D shaped and has narrow, pointed shoulders to the the gemstone. Both claw- and rub-over set diamonds have been around for a while, going in and out of popularity with the whim of fashion and both styles are easy to find in a vintage engagement ring.
Three stone, or trilogy rings, are just that: rings with three stones, and these can be all diamond or a combination of diamond with sapphire, emerald or ruby. A diamond three stone ring can have all the diamonds the same size or a slightly larger centre stone. When the combination is a diamond with another precious gemstone, then it's generally the sapphire, ruby or emeral that takes centre stage with a smaller diamond to each side. This style of engagement ring does tend to suit a larger hand although if you're petite and have set your heart on a trilogy engagement ring, you might just need to choose three smaller diamonds, perhaps all of the same carat weight (or size). A variation on this is the three stone twist where the shoulders rise up and almost hug the gemstones, it's an elegant and feminine shape which may also have further, smaller diamonds grain set into the twisting shoulders.
Popular from about the 1920s the two stone twist is another elegant style. With one side set with a diamond, the second half the twist is usually seen with a pearl, sapphire, emerald or, indeed, another diamond. Like the three stone twist, the gemstones may be claw or rub-over set and the shoulders may also be grain-set with smaller diamonds
Cluster style rings come in all shapes and sizes too, from round to oval or square and from Victorian times to a more recent vintage. Again, we have diamond clusters or diamonds partnered with other precious gemstones.
There is a trend for non-traditional engagement rings or engagement rings without a diamond, instead having a semi-precious gemstone such as pearls or opals. Whilst definitley pretty and certainly non-traditional, some caution must be exercised and they should be worn with care as many of these gemstones are not durable enough to withstand the day-to-day rigours of regular wear. Of course, if you job dictates that you may not wear jewellery or you're happy to keep you engagement ring only for special occasions, then a non-traditional, non-diamond engagement ring might be the ring of choice for you.