Rare gemstones are precious stones that are not commonly found in nature, making them highly sought after by collectors and jewelers. Examples include Alexandrite, known for its color-changing properties, and Tanzanite, which is only found in Tanzania. Their scarcity often leads to higher prices and unique value in the market. These gemstones are typically formed under specific geological conditions over millions of years. Factors such as color, clarity, cut, and carat weight contribute to their rarity and desirability. Other notable rare gemstones include Painite and Grandidierite, both of which are prized for their beauty and limited availability.