We will start from the bottom of the spectrum and make our way up to the highest quality. The lowest quality gold you can buy would be Gold Plated. This is only in technicality due to it's major availability, its high manufacturing and the fact that for a long time, the only thing available outside of pure gold was gold plated. There are different 'microns' you can plate your jewellery with, but most mass-produced jewellery brands will use the lowest which would be <1 micron. Gold Plated has a brass/copper/nickel inside which doesn't make them great for sensitive skin/ears and will stain your fingers that nasty green. Pros would be that gold plated should be cheap and affordable, don't get swayed by a price tag, plated is still plated no matter how high they inflate.
The next gold on our spectrum is Gold Vermeil. Although still plated, gold vermeil is great for sensitive skin as the inner core is sterling silver. Usually gold vermeil can be plated up to 3 microns in gold. It's always a great idea to ask the brand how many microns of plating their gold vermeil jewellery is, 3 microns being the highest. This jewellery you can't wear in the shower, you can wear it daily, but if worn in wet conditions will end up turning silver. This is because the gold will wear away and the inner core (silver) will start to show. A good quality, affordable choice of gold, depending on the microns.
Gold Filled is the next type of gold on our spectrum, being the best type of gold outside of solid gold. This is what we make we make our jewellery out of. Although a little more costly than it's counter parts, it's absolutely miles apart in quality. Gold filled isn't plated, rather the gold is fused to the inside metal, usually silver. This means we don't use 'microns' of gold, but rather a thousand% more gold content than plated jewellery. It won't rust or discolour, as the gold is made to last, and it can be worn daily even in the shower. This item is hot-off-the-press the newest in gold jewellery and is manufactured in the USA, not China. This means you can 100% trust the quality and standards.
The final and highest gold is of course Pure Gold, which is what we make our Finer Collection out of. There is no better gold to use than solid gold, we use 14k due to how beautiful the yellow is, it's not too rough or shiny. We also find 14k gold easier to work with and it does end up harder/firmer than 24k gold. You will find people saying solid gold is soft, but as long as you work on the pieces (As we do) they end up hardening in the process of making.