Last week the Kaliningrad Amber Combine pleased all stone lovers with the discovery of three unique amber nuggets at once.
The most difficult to cut is the native mineral - sulfur.
Aqueous calcium and aluminum fluoride with several additional anions, which is most often found in the form of white concretions, consisting of a microgranular aggregate.
Many minerals such as zircon, fluorite and even some garnets can contain significant admixtures of radioactive elements.
The now popular "invisible" setting, which makes it possible to create miniatures from cut gemstones, was first developed and applied by Van Cleef & Arpels in 1933.