I have now grown quite fond of Glass research. 
It will take 22 more hours to get the Mechanical Pen research completed normally, but since I havent used my glass I am very close to purchasing it’s completion early!
I am pillaging glass towns constantly, and I get +67/hr from my workers at a level 7 crystal mine. It’ll take less than 8 hours to get the research done, costing me about 5,000 glass… but, that’s 14 hours saved!
Current Research
Mechanical Pen
71%
22h 46m 45s
Accelerate research with crystal glass
You can complete the current research by adding crystals.
The amount required is dependent on the research complexity and the amount of research points already invested.
The closer the scientists are to their breakthrough, the less crystals are needed to be invested.
* Amount of crystal needed for completion: 5244
You still need 830 crystal glass in order to finish the research!