What is Rhodizite?
Rhodizite is a hard cubic alkali beryllium borate, valued for sharp tiny crystals, unusual chemistry and scarcity in evolved lithium-rich pegmatites.
Mineralogy and crystal structure
Reference formula: KAl4Be2(B,Be)12O28. Rhodizite is cubic and closely related to londonite, with caesium, potassium, lithium and beryllium substitutions across the series. Beryllium-bearing material is for careful display only. Rhodizite is classified with borates and has a cubic crystal system. Typical hardness is 8–8.5 on the Mohs scale and specific gravity is approximately 2.9–3.0.
Colour, lustre and habit
Typical colours include colourless, white, yellow, pale grey. The usual cubic, tetrahedral, granular habit and vitreous, adamantine lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Rhodizite forms in or is associated with highly evolved granitic pegmatites and boron-rich late-stage cavities. Important documented localities include Madagascar, Russia, Brazil, Myanmar and other specialised pegmatite localities.
Small cubic crystals with unusual pegmatite chemistry
Rhodizite is a specialist collector mineral whose value comes from the combination of hardness, cubic form and rare borate chemistry. A documented miniature can be more desirable than a larger generic specimen.
Collecting and care
Do not cut, grind or generate dust. Protect small crystals from impact and retain matrix and locality documentation.
