In this question, we are asked to spot the odd item from a given list. The options are: 1) Basalt, 2) Ruby, 3) Emerald, and 4) Sapphire.

Basalt is the correct answer because it is the only item in the list that is not a gemstone. Basalt is actually an igneous rock formed from the rapid cooling of lava.

Ruby, Emerald, and Sapphire, on the other hand, are all precious gemstones. Ruby is known for its deep red color, Emerald is known for its vibrant green color, and Sapphire is known for its blue color (though it can come in other colors as well).

Therefore, the odd item in the list is Basalt as it is not a gemstone, while the others are.