Possible Fossilized Dinosaur Egg Cluster
Jurassic to Cretaceous Periods
Excavation Source: East Asia
Approximate 16" length bed; no weight given

While it is possible that this is a fossilized nest example; from images alone I have come to the conclusion that this example is geologic. I believe these are concretions. Concretions are a mass of tightly compressed minerals that often form in sedimentary rock. 
While they can appear similar to eggs, especially in their smooth, round, or oval shapes, differences do exist. 1. Composed of rock minerals, which often have a different, denser composition toward the center. This color change can be visible when a concretion is broken. 2. The surface is typically smooth, with little texture, though some may have a few bumps or circular bands. 3. Concretions do not have an eggshell. Any fragments that break off will be solid and smooth on both sides. 4 Color and size: They tend to be dull, earthy colors; and they can range significantly in size, from a few millimeters to over 10 feet in diameter.

I looked for the following to determine, from images, the makeup of your example. 1. The presence of an eggshell. Concretions do not have them. 2. A broken concretion will show a mineral composition that is often different in the center, not an internal egg structure. 3. If a spherical or oval object is larger than 8 inches in length, it is likely a concretion, not an egg. 4. Rock that exactly matches the shape of a modern chicken egg is almost certainly a concretion.

The definitive sign of a genuine egg is the presence of an eggshell. Because eggs vary widely in shape, from elongated ovals to perfect sphere, shape is not a reliable indicator. Instead, paleontologists look for the unique surface ornamentation of the eggshell, which can include small bumps, ridges, and channels, and is visible with the naked eye or a hand lens. These textures can help distinguish between different types of eggs. While individual fragments of eggshell are common in some geologic formations, a larger grouping of eggshell is a more significant discovery.

As this is a valuation form images alone, I do suggest an in-person assessment. You can request an appointment with a regional natural history museum or university department. Fossilized egg clusters range in auction results from $1200 to $3000 (USD).

Previously: Dear Sebastian,

Thank you for contacting Mearto with your appraisal inquiry. You have added multiple items to be assessed. As this is a FMV for one item; I can give you an assessment for the items as a single collection. Or, you can select one item for FMV assessment and add the others as individual items.

Please let us know your choice.