Chalcedony with cassiterite BIRUG 24

BIRUG 24 is predominantly a specimen of chalcedony – a microcrystalline variety of silicon dioxide (quartz being the most usual and recognisable silicon dioxide form), but also contains cassiterite (tin oxide) – the primary ore of tin. Scientifically speaking, "chalcedony" describes sub- and microscopic "fibrous" quartz crystals, but more generally it can include all microcrystalline varieties of quartz including jasper, agate, carnelian and onyx. It usually displays a botryoidal crystal form (grape-like). The name comes from the town of "Chalcedon" mentioned by Agricola (1546) (now called "Kadıköy" – a district in Istanbul). Cassiterite is named after the "Cassiterides" meaning 'islands off the west coast of Europe' in pre-Roman times. It is debated as to where this means exactly, current possibilities include Ireland and Great Britain, or even mainland Spain. This specimen was donated to the Museum in 1915 by W. McLean and was digitised by Courtney Szanto, using an Artec Spider 3D scanner. Source: Objaverse 1.0 / Sketchfab