Gold filled is 14K gold bonded with brass. It is stronger and higher quality than gold plated which is why we like to use it for a more affordable gold-look option! Gold plated is a gold coating over top of sterling silver or any number of low cost base metals. We like to avoid this unless we're reworking vintage materials. Solid gold is marked as 24K, and we work mainly with 10K, 14K and 18K (true gold metal combined with another metal.) These karats are the best and most common for jewellery as they offer beautiful colour, strength and longevity.