Ravi Māṇikya

माणिक्यं दिननायकस्य
māṇikyaṃ dinanāyakasyā

Translation: māṇikyam (ruby etc. māṇi) is is the gemstone of the lord of the day (Sūrya)
Notes: dinanāyakasya — of the lord of the day (Sūrya) > → Ruby is the gemstone of the Sun
The formula is māṇikya ↔ Sūrya

Understand Ruby

Ruby is chemically a form of the mineral corundum, whose composition is aluminium oxide (Al₂O₃). What makes it a ruby rather than a colorless sapphire is the presence of trace chromium (Cr), which substitutes for some aluminium atoms in the crystal lattice and produces the red color.
Mineral species: Corundum
Chemical formula: Al₂O₃ (aluminium oxide)
Chromium content: Small amounts of Cr³⁺ ions incorporated into the lattice
Color origin: Chromium causes the characteristic red hue; pure corundum is colorless.
Ruby = Aluminium oxide (Al₂O₃) + trace chromium (Cr³⁺); This combination, under high temperature and pressure, produces the red variety of corundum known as ruby.

Crystal Properties
Crystal system: Trigonal (hexagonal scalenohedral)
Hardness: 9 on Mohs scale (second only to diamond and moissanite)
Specific gravity: ~3.97–4.05
Refractive index: ~1.762–1.770

Primary Maṇipūra Śloka

Translation: In the region of the navel is the Maṇipūra chakra, a lotus of ten petals.
nābhi‑deśe — in the region of the navel; sthitaṃ cakram — there is a chakra; daśāram — having ten petals; maṇipūrakam — the Maṇipūra (city‑of‑jewels) chakra

Meanings: A ten‑petalled lotus, shining like yellow fire;
A red, downward triangle (Agni‑tattva) in the center
Bīja: रं raṃ
Deity: Rudra or Vahni
Śakti: Lākinī

Translation: By saṃyama on the navel‑chakra, knowledge of the structure of the body arises
Petal‑Mantras of Maṇipūra: The ten petals bear the following Sanskrit letters: ḍaṁ, ḍhaṁ, ṇaṁ, taṁ, thaṁ, daṁ, dhaṁ, naṁ, paṁ, phaṁ
Bīja‑mantra: raṃ (रं) — the seed syllable of Agni