What is plumb gold?

Plumb gold refers to gold that has a minimum purity of 95%. The term "plumb" comes from the Latin word "plumbum," which means "lead." This is because, in the past, lead was used to mark the quality of gold. Plumb gold is sometimes called "four nines gold," referring to its purity of 99.99%. It is commonly used in jewelry making and has a slightly darker color than gold with a lower purity. Plumb gold is also more durable and less likely to tarnish than lower purity gold. However, it can also be more expensive due to its higher purity.