[en] When the TLD is used for Radiation Dosimetry, the calibration curve is produced by plotting increasing TL intensity as function of dose. There are cases where the TL intensity decreases as dose increases and can be used in radiation dosimetry. Such behavior can be found in green quartz, three varieties of beryl and pink tourmaline. In all these silicate crystals we can show that if we irradiate with increasing γ-dose there is a dose D_m for which the TL intensity is maximum. Of course, D_m varies depending on the crystal and irradiated crystal with the dose D_m is stable. If we take one of these crystals and irradiate with dose D_m and we irradiate with doses from low values up to 400-500 Gy we obtain a curve of decreasing TL intensity, such curve can be used as calibration curve. (authors)