Valmiki Ramayana Aranya Kanda Sarga 43 Shloka 32
Original Shlokaतत्सारमखिलं नृ़णां धनं निचयवर्धनम्। मनसा चिन्तितं सर्वं यथा शुक्रस्य लक्ष्मण।।3.43.32।।
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लक्ष्मण O Lakshmana, अखिलम् all, तत् all that, सारम् essence, धनम् wealth, नृ़णाम् of men, मनसा in the mind, चिन्तितम् thought over, सर्वम् all, शुक्रस्य यथा like Venus (Venus controls prosperity leading to procreation), निचयवर्धनम् growth of treasure.
O Lakshmana the essence of forest wealth is mineral wealth, which helps the growth of the treasury. It is conceived mentally as in the case of Venus.