BAVENITE (has been named after the place of discovery within Baveno, Italy * EN: bavenite, duplexite; DE: Bavenit; FR: bavenite; ES: bavenita; RU: бавенит) is the mineral, the beryllium silicate of the sub-class of the island silicates, Ca4[Be2Al2Si9O26](OH)2. The content of the BeO is from 5.5% to 9.3%. The impurities are: Na, F3+, Mn, and others. It crystallizes itself into the rhombic crystal systems. It forms the acicular and tabular crystals, more often the radiating and tabular aggregates. It is colourless or coloured into the grayish and pinkish tones. The cleavage is perfect along one direction. The hardness is 5.5-6. The density is approximately 2700 kilograms per cubic metre.

It is relatively rare. It may be found within the hydrothermal deposits, where it develops itself as the replacement of the early beryllium minerals (beryl, phenakite, and others), and also in the form of the independent isolates. It associates with carbonates, fluorite, feldspars, and so on. It is also known within the beryllium-containing skarns and granitic pegmatites.

In case of the significant clusters, it is the potential Beryllium ore.