claim: Mikhail Prokhorov fathered the former chairman of Russia's largest gold producer.
evidence: Hydroxylapatite , also called hydroxyapatite -LRB- HA -RRB- , is a naturally occurring mineral form of calcium apatite with the formula Ca5 -LRB- PO4 -RRB- 3 -LRB- OH -RRB- , but is usually written Ca10 -LRB- PO4 -RRB- 6 -LRB- OH -RRB- 2 to denote that the crystal unit cell comprises two entities .. crystal. crystal. mineral. mineral. apatite. apatite. Hydroxylapatite is the hydroxyl endmember of the complex apatite group .. apatite. apatite. hydroxyl. hydroxyl. endmember. Endmember ( mineralogy ). apatite group. apatite. The OH − ion can be replaced by fluoride , chloride or carbonate , producing fluorapatite or chlorapatite .. ion. ion. fluoride. fluorine. chloride. chlorine. carbonate. carbonate. fluorapatite. fluorapatite. chlorapatite. chlorapatite. It crystallizes in the hexagonal crystal system .. crystal. crystal. hexagonal. hexagonal ( crystal system ). crystal system. crystal system. Pure hydroxylapatite powder is white .. Naturally occurring apatites can , however , also have brown , yellow , or green colorations , comparable to the discolorations of dental fluorosis .. dental fluorosis. dental fluorosis. Up to 50 % by volume and 70 % by weight of human bone is a modified form of hydroxylapatite -LRB- known as bone mineral -RRB- .. mineral. mineral. human bone. human bone. bone mineral. bone mineral. Carbonated calcium-deficient hydroxylapatite is the main mineral of which dental enamel and dentin are composed .. mineral. mineral. dental enamel. dental enamel. dentin. dentin. Hydroxylapatite crystals are also found in the small calcifications -LRB- within the pineal gland and other structures -RRB- known as corpora arenacea or ` brain sand ' .. pineal gland. pineal gland. corpora arenacea. corpora arenacea