Just purchased a sample of what I believe to be slag glass. Rich green in color no U.V. reaction so its not uranium glass. Has very clear appearance internally hardly any bubbles but does have small white patches of inclusions. Also has Phantom crystal pockets that are roundish in shape with a growth structure similar to Malachite but is light mint green. I know very little about this type of material and I am needing as much accurate information on this as possible. Will take pics and post soon. Thank you all in advance for your consideration and help.
Good picts! The bottom side is the thermal shock portion (opaque greenish white) where the molten slag made contact with the ground cover. This produces a flash of steam from the moisture content which rapidly cools the material. There seems to be some additional darker gray material which is also slag in nature (heavier).
You can see structures and pits that look like imprints from gravel/pebbles/stones. Since the glass cooled rapidly, it did not adhere to the ground matrix.
Some sources of slag can contain elevated levels of lead, arsenic, and other heavy metals, due to the smelting processes. Cutting and faceting this material may require extra precautions for the cutter.
Many years ago, this type of material was sold to the aquarium enthusiast trade as decorative ornaments. Unfortunately, the hobbyists found these leaching toxic metals into the water, killing the aquatic occupants. The aquarium glass ornaments being sold nowadays is cullet glass (refined glass), which comes from art studios and glassware manufacturers.