Leland Blue is found in Northern Michigan and is a byproduct from the smelting processing during the 1870-1880’s. Leland, Michigan was an industrial town and when the smelting industry failed, large heaps of slag were dumped into lakes around Leland. Slag is a byproduct of the smelting process when raw ore is heated and once cooled the result is a stone-like “slag”. Leland Blue specifically is the mix of blue glass with other chemicals, but it can be found in shades of green, purple, or even gray. Today, many locals and tourists find this slag material on the shores of Leland’s beaches. Because of its hardness, it can be cut, polished, and made into jewelry very similar to natural gemstones. For this reason, Leland Blue had become an industry into itself, as it is highly collectable because of the beauty that can be found once the slag is cut, polished, and shaped. They can be very smooth, or they can be rough and pitted from air bubbles. In either case, Leland Blue is highly prized, collectable, and can be made into beautiful jewelry.
(from Garland’s Jewelry)
Rosarita is a unique material, which derives its exceptionally rich, red color from the process of gold refining. It is a unique by-product of the 1960s and 1970s gold refining processes. Alaskan beach sand was smelted for its gold content and the slag by-product was Rosarita, which is essentially a gold-infused glass. The base material for Rosarita is silica (which is quartz particles) mixed with gold at high temperatures.
Old processes prior to 1960 used the old method of open crucible and fire (infused heat) to smelt the sand, leaving behind a glassy-like material in the crucible, which is known as slag. This gold slag was used in the 1940s through 1970s for jewelry, carvings, flint napping, etc. This material known as Rosarita is some of the most exceptional colored gold slag ever produced. Most other slag were mostly red in color but not nearly as vivid as the magnificent Rosarita.
Rosarita is no longer produced because of improved efficiency in gold refinement. Modern processes extract nearly all of the gold out of the sand, leaving an un-remarkable clear glass slag without the deep red color that makes Rosarita so beautiful.