The glass catalog format consists of a set of descriptions
    of various materials.  Each material in a table:

        MATERIAL_NAME
            {
            ...
            }

    where the ellipsis represents the information relative to
    the material (e.g.: BK7).  This information consists of
    simple items and subtables (recursively, i.e.: subtables
    may contain either items or additional subtables).

    A simple item is in the form:

        ITEM_NAME:  item_value;

    where ITEM_NAME is the name of the item and item_value is
    its value.  Item values may either be numeric or string.
    If it is a string value, that string is contained within
    a pair of double quotes.

    A subtable is in the form:

        SUBTABLE_NAME:
            {
            ...
            }

    The ellipsis again here represents the data relative to
    that subtable.

    --------------------------------------------------------

    The following is a representative sample of the various
    subtables and values that may be found, based upon the
    Schott catalogs.  It should be noted that not all of the
    items need be within the data.  This may be indicated by
    either the item not being presented or by not presenting
    a value for the item.

    ----

    Standard values (indices for d and e
      lines; relative partial dispersion g to F):

        vd nd ve ne PgF

    Internal plot variables for the Schott
    program (?):

        plot_nd plot_Pg

    The six-digit designation for the glass:

        icode

    The "table" of refractive indices for some fixed
    wavelengths.

        n2325 n1970 n1529 n1060 nt ns nr
        nC nC' n632 nD nd ne nF nF' ng nh
        ni n334 n312 n296 n280 n248

    The dispersion coefficients, used to calculate
    the refractive indices at wavelengths not in the
    table (the exact formula used is given by the
    item dispform, and is applicable in the range
    of lambdamin to lambdamax):

        B1 B2 B3 C1 C2 C3

    The dispersion coefficients used to calculate
    the variation in refractive index with temperature:

        D0 D1 D2 E0 E1 lamdaTK

    The 10 mm 80% and 5% transmittivity wavelengths
    (on the blue end):

        lamda80 lamda05

    The partial dispersions (based upon nd and vd):

        Pst PCs PdC Ped PgF Pih

    The partial dispersions (based upon ne and ve):

        P'st P'C's P'dC' P'ed P'gF' P'ih

    The difference between the nd-vd partial
    dispersions from a "normal line" (based upon
    the Schott glasses K7 and F2):

        delPCt delPCs delPFe delPgF delPig

    The thermal coefficient of expansion, for the
    ranges -30 .. 70 and 20 .. 300 degrees C.

        alpham30_70 alpha20_300

    Transformation temperature:

        Tg

    Temperature of viscosities 10^13 and 10^7.6 dPa s:

        T10_13 T10_76

    Specific heat capacity:

        cp

    Thermal conductivity:

        thermConduct

    Density:

        roe

    Elasticity modulus:

        E

    Poisson's ratio:

        mu

    Stress optical coefficient:

        K

    Knoop hardness:

        HK

    Grinding hardness( relative to SK16, which has a
    Knoop hardness of 600 ):

        HG

    Bubble quality:

        B

    Resistence to water vapor, staining, acid, alkali,
    and phosphate:

        CR FR SR AR PR

    Transmittivity for a 5 and 25 mm thickness
    at a fixed set of wavelengths:

        tao5mm
            lam_2500 lam_2325 lam_1970 lam_1529
            lam_1060 lam_700 lam_660 lam_620
            lam_580 lam_546 lam_500 lam_460
            lam_435 lam_420 lam_404 lam_400
            lam_390 lam_380 lam_370 lam_365
            lam_350 lam_334 lam_320 lam_310
            lam_300 lam_290 lam_280 lam_270
            lam_260 lam_250

        tao25mm
            lam_2500 lam_2325 lam_1970 lam_1529
            lam_1060 lam_700 lam_660 lam_620
            lam_580 lam_546 lam_500 lam_460
            lam_435 lam_420 lam_404 lam_400
            lam_390 lam_380 lam_370 lam_365
            lam_350 lam_334 lam_320 lam_310
            lam_300 lam_290 lam_280 lam_270
            lam_260 lam_250

    Melt frequency
      "I"   -> frequently
      "II"  -> regularly
      "III" -> seldom
      "IV"  -> special order:

        meltFreq

    Availability
      "V"   -> preferred
      "S"   -> standard
      "A"   -> inquiry
      "X"   -> obsolete

        avail

    Relative price (BK7 == 10.0):

        rel_price

    Dispersions F to C and F' to C':

        nF-nC nF'-nC'

    Tables of temperature coefficients of refractive
    indices for three temperature ranges and three
    selected wavelengths (both relative and absolute
    variations are given):

        delndelt_rel
            wav_1060
                Tm40_m20 T20_40 T60_80
            wav_e
                Tm40_m20 T20_40 T60_80
            wav_g
                Tm40_m20 T20_40 T60_80

        delndelt_abs
            wav_1060
                Tm40_m20 T20_40 T60_80
            wav_e
                Tm40_m20 T20_40 T60_80
            wav_g
                Tm40_m20 T20_40 T60_80