Accessory phases include titanite, apatite, corundum, zircon, magnetite and ilmenite. Magnetite, zircon, apatite, ilmenite, biotite, and garnet are common accessory minerals. Other minor inclusions are sphene, apatite, rutile, zircon, and sphalerite. Other common accessory minerals are apatite, titanite, zircon and opaques. Beach sands include the minerals Ilmenite, rutile, zircon and monazite. The titanium minerals are mostly anatase and rutile, and zirconium occurs in the mineral zircon. Zircon (ZrSiO) and the cubic zirconia (ZrO) are cut into gemstones for use in jewelry. Different methods in detrital zircon analysis yield different results. Titanium (ilmenite) extraction was significant, as well as that of zircon and rutile. The sands on the island contain rutile and zircon. Martin Heinrich Klaproth discovered zirconium when analyzing the zircon containing mineral jargoon in 1789. Hafnium and zirconium occur together in minerals such as zircon, cyrtolite and baddeleyite. The crystal structure of zircon is tetragonal crystal system. Other orthosilicates include zircon, staurolite, and topaz. This give rise to a natural complexity of associating detrital zircon populations and their sources.