Formula: NaCaCu₅(PO₄)₄Cl · 5H₂O

Species: Phosphates

Colour: Light blue, bluish green; blue in transmitted light.

Lustre: Pearly

Hardness: 4

Specific Gravity: 3.2

Crystal System: Orthorhombic

Member of: Lavendulan group: The phosphate analogue of Lavendulan. An uncommon mineral in the oxidized zones of copper deposits in arid climates; also occurs as a rare mineral in caves.

Name: Named by Cornelius Hurlbut Jr. in honor of Mr. Matt Sample, Mine Superintendent for the Chile Exploration Company in 1921 (on staff as early as 1915) in Chuquicamata, Chile.

Type Locality: Chuquicamata Mine, Chuquicamata District, Calama, El Loa Province, Antofagasta, Chile