Cuprite Value and Jewelry Information
Cuprite is a mineral found in gems. Poorly cut cuprites appear as dark and dull and the quality cutting bring out the striking red colors and near metallic luster and also boosts their value.
It has been found that crystals of cuprite (copper oxide ) are typically too small and they are also opaque mixed with copper-bearing minerals, such as malachite, chrysocolla and azurite. Cuprite is also mixed with copper ore to form as a patina on copper and bronze artifacts.
Sometimes, cuprite often pseudomorphs into malachite, means it has a chemistry similar to malachite while retaining cuprite’s external crystal form. In the reflected light, cuprites may appear as bluish and in transmitted light, cuprites can show their deep red colours.
Cuprite’s have very high refractive index of 2.848 and specific gravity of 6-6.14, and this usually helps to differentiate cuprites from gemstones with similar color and appearance, especially more popular red gemstones like garnets, rubies and spinels. However, other rare red gemstones of similar appearance – such as proustites, rutiles and wulfenites also have over limit refractive index that overlaps of cuprite.
Cuprites have a deep brownish color and sometimes also found in light brown color. It should be notes that streak testing is destructive and should only be conducted as a last resort for identification and never on a finished gem.
Cuprite is an isometric crystal and has no birefringence or pleochorism, but some traces may also be present. Polishing faceted crystal with diamond paste may leave surface deformations that can cause anomalous birefringence.
Synthetics of Cuprite
Cuprite is synthesized by the scientists for various purposes, including research and into anti-fouling pains, the removal of patinas from bronze archeological finds, and other chemical and mineralogical processes. Artisan has used cuprite for colouring the glass bead since ancient times and the practice continues even in the modern times.
As a mineral, cuprite occurs in many locations. However, to date, only one locality i.e. Onganja, Namibia has produced blood red crystals transparent and large enough to facet. But now, this mine has been closed and doesn’t produce enough cuprite. Other good sources of cuprite includes: United States, Montana, New Mexico, Santa Rita, Pennsylvania and Utah.
Care of Cuprite
It has a hardness of 3.5 to 4, and it scratches easily and are not suitable for jewelry use. Over time, it also loses colour from exposure to light. Therefore, we should use protective settings for any cuprite jewelry pieces and reserve them for occasional evening wear. We should clean the gems only with water and mild detergent. Use soft brush for cleaning.
Due to copper content, the dust of cuprite is toxic and if accidentally ingested, it could lead to acute distress, like vomiting and kidney damage. So, faceters should wear protective masks and, ideally, use a glove box to prevent inhaling or ingesting cuprite particles during cutting, polishing, and cleaning.
It is not with the cuprite only, the cutting of gemstone releases large amount of dusts and smoke, therefore, the faceters should wear proper masks during mining of the gemstones.