Crassula 'Tom Thumb' is a charming miniature plant with tiny triangular leaves in opposing ranks on stems. The tiny mint green leaves have colorful reddish edges especially in bright light. It is topped by clusters of tiny white flowers in spring. Similar to Crassula perforata, ‘Tom Thumb’ is thought to be a hybrid cross as described in the Lexicon of Succulent Plants by Hermann Jacobsen as a cross between Crassula rupestris ssp. rupestris and Crassula rupestris ssp. marnieriana. Crassula "Jade Necklace" is considered a hybrid between Crassula falcata ("Propeller Plant") and Crassula marnieriana. Forms shrubby stems with short, ovate grayish-green triangular leaves. Leaves are very fleshy and margined with rose-red in bright light. Leaves are arranged along the stem in opposing pairs, with some resemblance to portions of a necklace. Crassulas require very porous soil with excellent drainage. In habitat, usually grow in rocky quartz fields. Bright, filtered light and ample airflow. Water thoroughly when soil is dry to the touch. Water with caution in winter, as the plant can lose its roots if the soil stays cold and wet for extended periods. Summer dormant. Protect from frost to prevent scarring.