Database of luminescent Minerals

Ludus Helmontii

Chemical Formula:See septaria

Familly: Rock


Mineral for Display: No


UV Type Main color Intensity Observation Frequency
Long Waves (365nm):      Yellowish White
Mid waves (320 nm):      Yellowish White
Short Waves (254 nm):      Yellowish White
Other colors LW:                    
White , Bluish White , Pale Yellow , Greenish white ,
Other colors MW:                    
White , Bluish White , Pale Yellow , Greenish white ,
Other colors SW:                    
White , Bluish White , Pale Yellow , Greenish white ,

Phosphorescence (in the common meaning of the term) seen by naked eye:

UV Type Color Intensity Observation Frequency
Long Wave (365nm): Greenish white
Mid Waves (320 nm): Greenish white
Short Waves (254 nm): Greenish white


Ludus helmontii is an old synonym for septaria. (see picture of the label of the specimen)

Ludus Helmontii Stellatus: septaria from the Kent (UK) containing fibroradiated xls of Baryte. (Chambers Encyclopedia)


Ludus Helmontii : (From its resemblance to a die). A roundish mass, which seems to have cracked in drying, and the interstices to be filled up by a calcareous matter, which frequently rises above the surface. The whole is an argillaceous clay, and the mass consists of prisms of different sizes separated by the calcareous matter. See Hauy, iv. 455. (from the book The London Medical Dictionary, by Bartholomew Parr.)

Main Activator(s) and spectrum:

Most Common Activator: Organic impurities

No spectrum for the moment

Best Locality for luminescence(*):

(*)Data are not exhaustive and are limited to the most important localities for fluorescence

Bibliographical Reference for luminescence:

Mineralogical Reference on internet: helmontii helmontii.shtml

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