1871
During vertebrate skeletal development , osteoblasts produce a mineralized bone matrix by deposition of hydroxyapatite crystals in the extracellular matrix .
 Chemical: hydroxyapatite
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: hydroxyapatite