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Mineral, Crystal or Glass


Hi! I am only now at 39 discovering my love for geology so I am hoping for some input. I collect most of my findings on beaches, I want to point that out hoping it will help. There is an abundance of seaglass where I live (North East Atlantic Canada) as well as raw gemstone and crystal from what I am discovering. I find it tends to be difficult to get information on and I struggle in particular with questions pertaining to whether a specimen is simply glass or is it more. I was hoping by some pictures maybe someone can offer some input.

I have more pictures to upload but will start with these.
Any information or help would be appreciated!


First of all Shandy, seaside, material is overwhelmingly, as you imply, only glass. But we also know that if you grub around in stream beds you can occasionally find crystalline bits. Witness the fine river gravel from Ceylon (Sri Lanka). If the upstream drains hard, pegmatitic rock there is a chance that excellent crystalline material can be found. I found a 57 carat, clear quartz, faceting grade piece not far from New York City on the Connecticut coast. Brazil produced ton quantities of stream worn quartz for the WWII radio transmitter oscillators. But let’s be realistic, most seaside clear bits are just plain glass. Pretty but nevertheless glass. It even facets beautifully. So why not have a category in your faceted stone collection “Seaglass”.


You have an awesome collection of sea glass that some people would kill for and some people would work hard to fake. Yep seaglass is faked all the time and sold as the real thing. Seaglass jewelry is quite popular right now and is easy to make if you can wrap it with Sterling any 14k gold.
All the best,


I actually began collecting seaglass, and yea I have seen many posts about fake glass. Thank You again!


Thank You, I will do just that I think. I have quite a bit…


I agree with everyone it looks like sea glass based on the sharp edges on the glossy pieces and smoothed out edges on the matte pieces but the colors and shapes are very beautiful. Some of them would be very beautiful once set in metal - even if in a beautifully formed tiled mosaic. If you have pieces that are not as flat in this collection I definitely would re-upload some different angles just to make sure though. That would be nice if all of them were emeralds, aquamarines & sapphires! :star_struck:



I agree with previous posters that appearance and shape (thin, sometimes concave pieces that come from cylindrical shapes, often abraded by sand (=quartz, harder than glass). Older glass will also sometimes have bubbles (not often seen in visible sizes in modern glass), some glass will have"swirls" in it. Most quartz pebbles will not show conchoidal fracture, whereas all glass will show conchoidal fracture where freshly broken. An easy start to ID what’s found on the beach would be a $10 to $15 gem scale found on ebay (100g x .01gm) and a small plastic cup such as used for salad dressing. Fill cup with water, tie specimen with string, use tare button to zero out weight of cup + water. Lower specimen into cup until it rests on the bottom of cup…this gives specimen weight in air. Then suspend specimen in the water with the string and read weight in water. Weight in air/weight in water=specific gravity. Knowing SG will separate most glasses from quartz, which has a higher SG, as do most other minerals. Get some known materials together for a set of rough and ready “hardness points” and you have the beginnings of a field ID set. Things to use are listed in lots of mineral books for kids (knife, copper penny, piece of known quartz, piece of bottle glass, etc.). As they used to say in math texts, “the student should work this out for himself.” HTH, royjohn