Assertion: glass's alumina | /r/HasProperty | typically 2.5%
Facets:
Source sentences:
text: The major component of the glass is silica, which during the Roman period was sand (quartz), which contains some alumina (typically 2.5%) and nearly 8% lime.  
text: The major component of the glass is silica, which during the Roman period was sand (quartz), which contains some alumina (typically 2.5%) and nearly 8% lime.