Now, let's look at physical Bitcoins as a concept. Physical Bitcoins have been around for years, but they are not part of the mainstream trading platforms. There are very few companies that are involved in this untried and relatively raw industry. Some try to appeal to consumers through quality and the use of precious metals, such as gold and silver. Some offer good designs at relatively low prices, while some offer neither of these. The market for physical coins is very limited, and this is a place for collectors. Rather than being truly practical, physical Bitcoins are usually marketed as conversation pieces, such as limited series collectibles. At times, these are also referred to as "gifts for geeks". Some of the well-known physical Bitcoins are Casascius, Titan Bitcoin, Alitin Mint, and Cryptomint Coins. There are other physical Bitcoins that are available that can be looked upon as collectibles.