Amber is generally more expensive than agate. This is due to several factors that influence the value of these gemstones.

Firstly, amber is a fossilized tree resin that is millions of years old, making it a rare and unique material. Its age and the rarity of high-quality amber contribute to its higher price. Additionally, amber is often found with inclusions, such as insects or leaves, which are highly sought after by collectors and can significantly increase its value.

On the other hand, agate is a variety of chalcedony, a microcrystalline quartz. It is more abundant and easier to find than amber, which makes it less expensive. While agate can come in a variety of colors and patterns, it lacks the historical significance and rarity of amber, which are key factors in determining a gemstone's value.

According to the American Gem Society (AGS), the price of amber can range from $50 to $100 per carat for lower-quality pieces, while high-quality amber with inclusions can sell for several thousand dollars per carat. In contrast, agate typically sells for a fraction of the price, with prices ranging from $1 to $10 per carat.

The rarity and historical significance of amber, combined with its unique properties and the demand from collectors, make it more expensive than agate. The natural beauty and the cultural value associated with amber also contribute to its higher price point.