The first step is to create the base. This can be made from cuttable stones or gems or from marble. Each item will be worth more points based on the rarity.
Then you have to create the lid. This is done on an anvil with different metals and of different qualities of workmanship.
Then you have to create the inlay for the lid. This uses cuttable gems and silver or gold to create dramatic patterns. Other gems can be used here, such as diamond or topaz, to add accents.
The Sarcophagus is now finished....almost. The next step is to gather exotic herbs for the embalming fluid, and cook it in a kettle until it's set.
The above points were kept purposely vague so that more user input can be added and the test can be perfected.