You can see from the image of the front of the CR-1 and the schematic below that this radio has two adjustable capacitors, one for antenna tuning (C1) and one for detector tuning (C2). There is also a switch (S1) that can add 0, 350 or 700 uF of capacitance to adjust the antenna tuning for a high, medium, or low part of the AM band. The detector is a glass encapsulated germanium diode.


References & Additional Resources:
Blog post by crystal radio enthusiast Steve, VE7SL.
https://www.amateurradio.com/the-enigmatic-heathkit-cr-1-crystal-radio/
Scott’s Crystal Radios describes the duplication of this radio from scratch.
http://oldheadphones.com/crystal/info/heath.htm
Full description found on Radiomuseum.org
https://www.radiomuseum.org/r/western_44001_1.html