Fossil fly in Baltic amber (polished; 16 mm across) from the Eocene of Yantarnyi, western Russia.

Fossils in amber are some of the most intriguing remains of ancient organisms anywhere in the rock record. Amber is fossilized tree sap (resin). Fossilized tree resin is technically called resinite. This piece of amber comes from the Baltics. Baltic amber is some of the most famous on Earth. Amber specimens from different localities are often given different varietal names. Baltic amber is a type of resinite often called succinite. Some amber specimens have body fossil inclusions, and others don't. The amber itself is a biogenic product, not a body fossil.

The Baltic amber shown here has a nice fossil inclusion. This insect is a fly (Animalia, Arthropoda, Insecta, Diptera, Brachycera). Note that this fossil fly is covered in a whitish milky material. That is a decay coating. This is commonly encountered in Baltic amber, and is one diagnostic method of identifying genuine succinite (there’s lots of fake amber fossils out there). This amber specimen also has lots of minute, stellate trichomes (not visible in photo) that are also unfakeable (I think). They are “down” - epidermal hairs on flowers & leaf buds from ancient oak trees. These are abundantly preserved in genuine Baltic amber.

Stratigraphy: “Blue Earth layer”, “Amber Formation”, Lutetian Stage, lower Middle Eocene.