Subject: the difference between crystal and fused quartz

I have been looking for some physical properties of quartz in 
data tables. Sometimes it says 'fused quartz' sometimes it says 
'crystal quartz'. Both is obviously SiO2, but the physical 
properties such as thermal expansion appear to be different, so 
what is the difference, what does 'fused' and 'crystal' mean?

Re: the difference between crystal and fused quartz