caldigger Posted March 1, 2014 Share Posted March 1, 2014 I have a simple question. What causes florescence in sea shells? I have found a few small cowry shells the other day. While checking my fossils with a UV light I noticed these shells fluoresced a very vivid bright magenta color. I am pretty sure they are not fossil shells. Any ideas? Do these snails see things in a different light and use the coloring for sexual identification? Sorry, I tried to take a photo of it but couldn't get the camera to cooperate with ultra violet lighting. Link to comment Share on other sites More sharing options...
PA Fossil Finder Posted March 1, 2014 Share Posted March 1, 2014 I think it is just what the shells are made of. Seashells are calcium carbonate/aragonite, and tiny amounts of trace minerals or the structure of the shell can cause shells to glow certain colors. I have bubble snails from SW Florida that glow an orangish-brown color. Stephen Link to comment Share on other sites More sharing options...
Mediospirifer Posted March 1, 2014 Share Posted March 1, 2014 I don't think mollusks see in ultraviolet. I know birds and some insects (bees) do, so flowers usually have patterns, and some birds' feathers. A lot of organic substances are fluorescent. Forensics uses this property to find blood traces, and raptors use it to find rodent dens. Cool stuff! Link to comment Share on other sites More sharing options...
New Members Seneca20 Posted March 1, 2014 New Members Share Posted March 1, 2014 I have some cowries from Australia (Cypraea venusta) that flourece a bright magenta under UV light. I was told it was the minerals that make up it's shell like aragonite. Only a few cowries in my collection do this. Link to comment Share on other sites More sharing options...
caldigger Posted March 1, 2014 Author Share Posted March 1, 2014 Thanks guys, always learning something new here. Link to comment Share on other sites More sharing options...
ted coulianos Posted March 3, 2014 Share Posted March 3, 2014 shining ultraviolet light on some Florida Pliocene fossil shells (especially volutes, miter shells, & cowries) often reveals ancient color patterns & spots glowing in bright orange on otherwise white chalky backgrounds; not sure if this has any scientific or forensic value, but interesting to observe none the less. The color pattern on a fossil volute is virtually identical to a modern Voluta junonia. Maybe worth a little photographic experimentation with different u.v. wavelengths?? 1 Link to comment Share on other sites More sharing options...
painshill Posted March 7, 2014 Share Posted March 7, 2014 Unfossilized shells are composed largely of aragonite with some calcite and both of those may fluoresce if the right amount of "activator" mineral(s) are present. Aragonite typically fluoresces a pale rose, yellow, white or bluish colour. Calcite typically fluoresces red, blue or yellow and a variety of other colours - but less usually so. In living (or recent) organisms - including molluscs - organic pigments that are part of the original colouration may also fluoresce. In many animals, that’s often an adaptation which helps attract mates (although not in molluscs) or deter predators that can see things in the ultra-violet parts of the spectrum which we cannot. In plants, it also attracts pollinating insects. As well as insects, fish and birds notably have the ability to “see” in the ultra violet parts of the spectrum. There's extensive discussion here: http://www.thefossilforum.com/index.php?/topic/41049-fluorescent-fossils-under-uv-light/ Roger I keep six honest serving-men (they taught me all I knew);Their names are What and Why and When and How and Where and Who [Rudyard Kipling] Link to comment Share on other sites More sharing options...
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