It goes by Streptanthus glandulosus. There are a number of distinct named varieties. The sepals are usually purple, like the petals, but may be white in sub-species albidus. In contrast to the delicate beauty of the flowers, the herbage is coarse and twiggy. The leaves are arrow-head shaped, with sharp teeth along the edges and stiff hairs.
Seed pods are a couple of inches long, pointing upwards.
You can find them all over the grassy slopes and ridges around the lab, but you have to look carefully, as the flowers are only about 1 cm long. Peak bloom is from April until June. The name is easy to understand. The flowers look like pieces of amethyst. Unforgettable, especially in bright sunlight.