Here's a bit of info/propaganda about the material that the pen is made out of, from the Visconti marketing materials:
"The material in this pen is as antique as the world: lava from the Etna volcano. Nevertheless, it has several characteristics that render it unique in the manufacturing of writing instruments. Visconti has successfully produced a material containing over 50% of pure basaltic lava, catalysed together with resin in a formula – patented thus obviously kept secret -whose extraordinary characteristics practically transforms it into a material perfectly fit to writing instruments."
This info comes from here.
If you would like more precise weights and measurements, you can find them here. (No affiliation with Goulet Pens, just gotta support the local retailer!)
Also, if you don't have time/the inclination to watch the video, here are my notes that summarize the key points of the review:
This pen was loaned to me for the purpose of review and I am not being compensated in any way. All opinions above are my own and you are free to disagree with me if you like.