This is an Awesome natural, pyrite specimen from Peru. It consists of a n enormous terminated pyrite crystal with a large covering of calcite crystals on top. The calcite brightly fluoresces red under long wave light. The fluorescence, I have found is very hard to photograph. It fluoresces a bright even red color about like the reddest color seen in the pics. I do not know what it does under short wave light, as I don't own a short wave lamp. I used a small handheld convoy long wave ...mineral flashlight in the photos. A proper lw light would do this specimen justice. It measures 115mm. x 98mm. x 93mm. 25mm = 1in. This is an excellent museum fluorescent specimen. Many of the fluorescent minerals you see look like rocks without crystalization visible. This is an amazing specimen without uv light. Don't forget to check out my other items, If you purchase more then one, wait to check out until you are done shopping, let me know you are finished, and I will send an invoice with combined shipping. UPDATE: I have now created new combined shipping rules for my listings. You will only be charged shipping on the item with the highest shipping cost. Each additional item is free and will be calculated for you when you go to pay. Thank You!