I have an egg I found in Herriman Utah. From what I have found on the internet I believe that the egg is a Himeoolihus. Which is the smallest Non-Avian Theropod egg known to date. Scientists estimate that the egg probably weighed about as much as a quail egg around 9.9 grams. The one I have weighs 7.6 grams. I have also attached a known Non-Avian Theropod egg picture. According to the website, Guinness World Records "a recent discovery, they have found a new type of theropod egg fossil that is around 45 mm tall and 20 mm wide, and weighs only around 10 grams – close to the weight of a quail egg." That egg was found in Japan. Thank you for taking a look at the pictures I have attached.
roughly 2.75cm x1.6cm
Unauthenticated Theropod Dinosaur Fossil Egg (possible Non-Avian Theropod)
Southwestern United States, Colorado Plateau
Cretaceous Period (66 million years ago) (possible Campanian)
The general shape and appearance of a Dinosaur egg fossil. Appears to have a thin layer of residual matrix on the shell. However; this can also occur in geologic concretions or chert nodules found in limestone deposits. An X-ray scan of the specimen or in-person assessment will assist in identifying age and if the specimen is geologic or biologic in development. Measurements: 2.75 cm x 1.6 cm; 7.6 grams weight.
From Images alone, I cannot give complete accuracy to you finding; but I do not disregard your research and the possibility that your example is a fossil. One aspect that gives me doubt: Most often a fossilized egg from these ancient eras will not break away from teh ground/matrix it fossilized within. The organic matter of teh earth and egg begin to fuse in most dinosaur egg examples. A churt or other mineral deposit will do so, because it is often surrounded by water or a less strong mineral that will allow it to become lose from the matrix it was in.
“The Fossil Forum” is open to research and asking questions on fossils; the link will open to their dinosaur egg guide. While posing a question on the form is open to all responses; many are well researched and provide additional peer reviewed articles. http://www.thefossilforum.com/index.php?/topic/92371-advanced-dinosaur-egg-guide/
In person authentication, age, and origin will affect the possible value of these specimens. I do suggest you look to the fossil form and ask for an in-person assessment with a regional University Geology department or Natural History Museum. Often, these organizations will host experts in paleontology to review public finds. Researching current auction price results of Dinosaur Egg Fossils; the expected fair market value would be in the range of 50 to 125 USD. With an in-person authentication to verify the specimens: a FMV could be achieved. It is important to recognize local, state, and US federal laws and prohibitions of sale and shipment of Fossils and Paleontology items.