Larvikite – this is feldspar from Larvik, Norway. Gray and black rock with pearlescent blue flash all over it. This is difficult to get a good picture of but all 3 definately have flash.
Largest cab measures 43mm x 18mm. Smallest cab measures 23mm x 25mm. Other cab measures 36mm x 12mm. All are ~7mm thick.
1 inch = 25.4mm.