Rubidium is an alkali metal (similar in chemistry to potassium and caesium). Applications for rubidium chemicals include biomedicine, electronics, specialty glass and pyrotechnics. Rubidium can also be used as a lower cost substitute for some caesium applications. Recent spot prices for rubidium metal have ranged from $36.00 per gram up to US$130.00 per gram (US$1080 to US$3640 per ounce) depending on purity.