An encyclopedia of the mineral kingdom.
Specimens
Pick a stone.
Tools
Three ways into a specimen.
Identification
Walk an unknown specimen through hardness, lustre, and streak to narrow it to a shortlist of candidates.
Periodic table
Tap an element to see every mineral it forms — iron, copper, silicon, and the exotic ends of the table.
Comparator
Stack two or three minerals side by side and read their physical and optical data in a single row.