Blog Archives

Collecting rocks, crystals and minerals

collecting crystals

Find great specimens of minerals, crystals, rocks and tumbled stones for your collection on bidorbuy.

Why we love and collect gems

Semi-precious stones

Precious stones may be rare, but many semi-precious stones are equally beautiful.

Gemstone spotlight: Pearls


Moh Hardness Scale: 2.5 to 4.5 Specific Gravity: 2.6 – 2.85 Refractive Index: 1.52 – 1.69 Colour: White, pink, yellow, silver, black, blue, green   Pearls are some of the oldest of all gemstones, perhaps the oldest. Valued since ancient times, specimens dating from the 6th century BC have been discovered. Traditionally seen as a […]

Are your treasures covered?


Insurance is a continuous expense that collectors do not always budget for.

The rarest gemstones you’ve never heard of

Since ancient times men have coveted the mineral riches of the earth. Iron, tin, copper, silver and gold have been valued since antiquity, alongside the various gems with which they share the dark rock.   The Ancient Greeks were the first to classify gems into two broad categories – precious and semi-precious stones. The original […]

Gemstone spotlight: Amethyst

Name: Amethyst Moh Hardness Scale: 7 Specific Gravity: 2.65 Refractive Index: 1.55 Colour(s): Purple, violet Once counted among the most precious of gemstones, the discovery of large quantities of Amethyst in Brazil during the 18th century led to a decline in the value of amethyst. Today it is marked as a semi-precious stone and it […]

Massive R1 Coins by Mail sale!

Coins By Mail  are having the sale of the decade with thousands of items marked down to a R1 starting bid! This exciting sale began earlier this week; and the best news is that Coins By Mail will be marking down a whole range of items for the next 2 months!   Coins By Mail currently […]

Gemstone spotlight: Alexandrite

Name: Alexandrite Moh Hardness Scale: 8.5 Specific Gravity: 3.7 Refractive Index: 1.76 Colour: Blue-green in daylight; pink-red in incandescent light     Alexandrite is precious gemstone with peculiar properties and a peculiar past. This gemstone exhibits a colour change effect, appearing green to blue in bright light, while in more moderate light it shifts to […]

Gemstone spotlight: Demantoid garnet

Name: Demantoid Garnet Moh Hardness Scale: 7.5 Specific Gravity: 3.84 Refractive Index: 1.9 Colour(s): Green   The garnets are a family of gemstones, and to the uninformed are regarded as a collective of less precious stones. However, there exist within this group certain types which command a high price, and none is more valued than […]

Gemstone spotlight: Topaz

Topaz gemstones are beautiful stones that have been valued since antiquity.