Complex sentence: Freshly prepared or fractured lead has a bright silvery appearance with a very slight hint of blue, but it tarnishes on contact with moist air, giving it a dull appearance whose hue depends on prevailing conditions.
Split into simpler sentences: Freshly prepared or fractured lead has a bright silvery appearance with a very slight hint of blue. Lead otherwise tarnishes on contact with moist air, giving it a dull appearance the hue of which will vary depending on the prevailing conditions.