▁but ▁he ▁res igned ▁that ▁post ▁in ▁ 1 8 6 9 , ▁retain ing ▁the ▁other ▁till ▁his ▁death . ▁From ▁ 1 8 5 0 ▁to ▁ 1 8 6 7 , ▁T enn ant ▁was ▁also ▁a ▁lect urer ▁on ▁ge ology ▁and ▁min eral ogy ▁at ▁the ▁Royal ▁Military ▁Academy , ▁W ool wich . ▁T enn ant ▁had ▁an ▁excellent ▁practical ▁knowledge ▁of ▁min er als ; ▁when ▁diam onds ▁were ▁first ▁found ▁in ▁South ▁Africa , ▁T enn ant ▁verified ▁that ▁they ▁were ▁indeed ▁genu ine . ▁ ▁T enn ant ▁was ▁an ▁earnest ▁advoc ate ▁of ▁technical ▁education , ▁giving ▁his ▁own ▁money ▁liber ally ▁to ▁help , ▁and ▁persu ading ▁the ▁Turn ers ' ▁Company , ▁of ▁which ▁he ▁was ▁master ▁in ▁ 1 8 7 4 , ▁to ▁offer ▁pri zes ▁for ▁excell ence ▁in ▁their ▁craft . ▁When ▁the ▁Koh - i - No or ▁diam ond ▁was ▁rec ut , ▁T enn ant ▁super int ended ▁the ▁work ▁In ▁ 1 8 4 0 , ▁he ▁becoming ▁min eral og ist ▁to ▁Queen ▁Victoria ▁in ▁ 1 8 4 0 , ▁taking ▁over ▁from ▁Sarah ▁Ma we ▁T enn ant ▁also ▁had ▁o vers ight ▁of ▁Miss ▁Bur d ett - C out ts ' s ▁collection ▁of ▁min er als . ▁ ▁T enn ant ▁was ▁elected ▁a ▁fellow ▁of ▁the ▁Ge ological ▁Society ▁in ▁ 1 8 3 8 , ▁and ▁president ▁of ▁the ▁Ge olog ists ' ▁Association ▁(