def olivine(piezometer=None):
    """ Data base for calcite piezometers. It returns the material parameter,
    the exponent parameter and a warn with the "average" grain size measure to be use.

    Parameter
    ---------
    piezometer : string or None
        the piezometric relation

    References
    ----------
    | Jung and Karato (2001) https://doi.org/10.1016/S0191-8141(01)00005-0
    | Van der Wal et al. (1993) https://doi.org/10.1029/93GL01382

    Assumptions
    -----------
    - The piezometer of Van der Wal (1993) requires entering the linear mean apparent
    grain size in microns calculated from equivalent circular diameters (ECD) with no
    stereological correction. The function will convert automatically this value to
    linear intercept (LI) grain size using the De Hoff and Rhines (1968) correction.
    It is assumed that LI was multiplied by 1.5 (correction factor), the final relation
    is: LI = (1.5 / sqrt(4/pi)) * ECD

    - The piezometer of Jung and Karato (2001) requires entering the linear mean
    apparent grain size in microns calculated from equivalent circular diameters
    (ECD) with no stereological correction. The function will convert automatically
    this value to linear intercept (LI) grain size using the De Hoff and Rhines
    (1968) empirical equation. Since LI was originally multiplied by 1.5 (correction
    factor), the final relation is: LI = (1.5 / sqrt(4/pi)) * ECD
    """

    if piezometer is None:
        print('Available piezometers:')
        print("'Jung_Karato'")
        print("'VanderWal_wet'")
        print("'Tasaka_wet'")
        return None

    elif piezometer == 'Jung_Karato':
        B, m = 5461.03, 0.85
        warn = 'Ensure that you entered the apparent grain size as the arithmetic mean in linear scale'
        linear_interceps = True
        correction_factor = 1.5

    elif piezometer == 'VanderWal_wet':
        B, m = 1355.4, 0.75
        warn = 'Ensure that you entered the apparent grain size as the arithmetic mean in linear scale'
        linear_interceps = True
        correction_factor = 1.5

    elif piezometer == 'Tasaka_wet':
        B, m = 719.7, 0.75
        warn = 'Ensure that you entered the apparent grain size as the arithmetic mean in linear scale'
        linear_interceps = False
        correction_factor = 1.2

    else:
        olivine()
        raise ValueError('Piezometer name misspelled. Please choose between valid piezometers')

    return B, m, warn, linear_interceps, correction_factor