The fundamental economic principle of supply and demand dictates that lower supply and higher demand lead to a higher price and perceived value. It has been no hidden truth that, Rarer items are often perceived as more valuable due to the scarcity principle, which suggests that the less something is available, the more desirable it becomes. This scarcity can be a signal of other desirable qualities, like higher quality, prestige, or unique attributes. Items that are made in very small quantities, or are unique one-of-a-kind pieces, are inherently rarer. For example, a first edition book, a limited edition painting, or a rare stamp. Bringing into limelight the all new importance of rare items Sanskrit says :
शैले शैले न माणिक्यं मौक्तिकं न गजे गजे |
साधवो न हि सर्वत्र चन्दनं न वने वने.||
Shaile shaile na maanikyam mauktikam na gaje gaje
Saadhawo na hi sarvatra chandanam na vane vane.
Shaila = Mountain.
Manikya = precious stones, like gems, diamonds etc.
Mauktik = Pearls. (It is believed that inside the skulls of some elephants, substance resembling round pearls is found, which is called 'Gaja Mauktik'.)
Saadhwo = Noble persons
Chandan = Sweet smelling wood of a sandlewood tree, which is found in the forests of Karnataka and a few other places.
Vana = Forest.
i.e. Gems and precious stones are not found in every mountain and all elephants do not have pearls inside their forehead. So also, noble persons are not found every where and sandlewood trees are not grown in all forests.
The underlying idea is that any thing which has special qualities is never found in abundance in this World. The rarer a thing is, the more value it carries.