enitoite is a small blue gemstone with unique properties, like sparkling brighter than diamonds. Those properties make it expensive: a single carat can cost over $12,000. But you can only really find this gem in one place. It's California’s state gem because facet-grade benitoite can be found in only one location: San Benito County. But a benitoite vein hasn’t been found there since the late 1990s. So why is benitoite so hard to find? And what makes it so expensive?