Hello, Newton, From images it is difficult to identify the example you have. I cannot tell, with one-hundred precent accuracy if this is a biologic fossil or a geologic formation of different types of sedimentary rock. I do, however, note three district areas of the example that do appear to be fossilized bone. The way the possible bone lies in the matrix does not give a clear form to what type of bone it may be or if it is multiple bones. I cannot identify an animal type, part of body, or era. The example measures 16cm x12cm x8cm, a weight will be helpful in future assessment. At this time, I cannot give a higher value than $30 USD. I do think it is worth exploring more and suggest you seek out an in-person assessment. You can schedule an appointment with a regional Geography or Anthropology Museum or University Department. Often, too, libraries and museums will host specialist days to bring an item in for valuation. You can introduce your items with the statement above. In addition, regional gem and mineral shows also have free assessments and can lead to lots of discussion about your example. I suggest not using products to "clean" the item. A biologist or geologist will be able to assess the item with out further removal or bleaching of materials. For display: I suggest a custom metal or wooden stand. A unique formation, such as this, can make a great display. In many cultures, and I immediately think of China, a scholars stone is used for decoration and meditation. Your unique example could be fashioned into a modern remake of those design pieces.
